Clip advancer with lockout mechanism

ABSTRACT

A surgical clip applier and methods for applying surgical clips to a vessel, duct, shunt, etc., during a surgical procedure are provided. In one embodiment, a surgical clip applier is provided and can include a housing having a trigger movably coupled thereto and an elongate shaft extending therefrom with opposed jaws formed on a distal end thereof. The clip applier can include an advancer assembly disposed within the elongate shaft and configured to advance one of a plurality of clips disposed within the elongate shaft into the opposed jaws. A feeder shoe can be disposed within the elongate shaft and can be configured to engage and prevent the advancer assembly from moving to a proximal position after the advancer assembly has moved to a distal position to advance a proximal-most clip into the opposed jaws. This can indicate to a user that a clip supply of the surgical clip applier is depleted.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. applicationSer. No. 12/576,736 filed Oct. 9, 2009 and entitled “Improved ClipAdvancer” which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates broadly to surgical devices, and inparticular to methods and devices for applying surgical clips to ducts,vessels, shunts, etc.

BACKGROUND OF THE INVENTION

Surgical clip appliers are commonly used for ligating blood vessels,ducts, shunts, or a portion of body tissue during surgery. Most clipappliers typically have a handle with an elongate shaft having a pair ofmovable opposed jaws formed on an end thereof for holding and forming aligation clip therebetween. The jaws are positioned around the vessel orduct, and the clip is crushed or formed on the vessel by the closing ofthe jaws.

Clip appliers that are configured to deliver multiple clips typicallyinclude an advancer mechanism that sequentially advances the clips intothe jaws of the clip applier. One problem associated with advancermechanisms is that there is generally no indication of when the clipapplier is out of clips. In the middle of a procedure, a surgeon orother user may continue squeezing the trigger of a clip applier to applyclips even after the last clip has been applied. With no indicationotherwise from the clip applier, the surgeon may believe he is closingan incision or other opening in tissue when he is not. Such a mistakecould be dangerous to the patient, and at a minimum, could cost thesurgeon valuable time in having to repeat at least a portion of theclosing procedure.

Accordingly, there remains a need for improved methods and devices forapplying surgical clips to vessels, ducts, shunts, etc.

SUMMARY OF THE INVENTION

The present invention provides method and devices for applying asurgical clip to a vessel, duct, shunt, etc. In one embodiment, asurgical clip applier is provided and can include a housing having atrigger movably coupled thereto and an elongate shaft extendingtherefrom with opposed jaws formed on a distal end thereof. An advancerassembly can be disposed within the elongate shaft and it can beconfigured to advance one of a plurality of clips disposed within theelongate shaft into the opposed jaws. In some embodiments, the advancerassembly can be movable between a proximal position and a distalposition. The surgical clip applier can also include a feeder shoedisposed within the elongate shaft and configured to engage and preventthe advancer assembly from moving to the proximal position after theadvancer assembly has moved to the distal position to advanced aproximal-most clip into the opposed jaws.

In some embodiments, movement of the trigger from an open position to aclosed position can be effective to move the advancer assembly from theproximal position to the distal position. The surgical access device canalso include a clip track disposed within the elongate shaft and havinga plurality of clips seated therein, and the feeder shoe can be slidablydisposed within the clip track to distally advance the plurality ofclips through the clip track. In one embodiment, the advancer assemblycan include a recess formed therein that is configured to be engaged bya tang on the feeder shoe to prevent the advancer assembly from movingto the proximal position after the advancer assembly has moved aproximal-most clip into the opposed jaws. The tang on the feeder shoecan be configured to move distally with the feeder shoe as the feedershoe advances the plurality of clips through the clip track.

The advancer assembly can have many configurations and can include afeed bar coupled to an advancer. The advancer can have a distal endconfigured to contact and advance one of a plurality of clips into theopposed jaws. In some embodiments, the recess can be formed through adistal portion of the feed bar and a proximal portion of the advancer. Aproximal portion of the tang can be connected to the feeder shoe and adistal portion of the tang can be disconnected from the feeder shoe andcan extend a distance below an inferior surface of the feeder shoe.

In other aspects, a surgical clip applier is provided and can include ahandle housing having a trigger movably coupled thereto and an elongateshaft extending distally therefrom. The elongate shaft can have opposedjaws on a distal end thereof. A clip advancing assembly can beoperatively associated with the trigger and it can be configured toadvance one of a plurality of clips disposed within the elongate shaftinto the opposed jaws. A lockout mechanism can be configured to lock theclip advancing assembly in place after the clip advancing assembly hasdistally advanced a proximal-most clip into the opposed jaws. The clipadvancing assembly can also be configured to lock the trigger in anactuated position when the clip advancing assembly is locked in place bythe lockout mechanism.

In some embodiments, the surgical clip applier can further include apawl and ratchet mechanism disposed within the handle housing andoperatively associated with the trigger. The pawl and ratchet mechanismcan have an engaged configuration in which the pawl and ratchetmechanism controls movement of the trigger and a disengagedconfiguration in which the trigger is movable independently of the pawland ratchet mechanism. The lockout mechanism can be configured to lockthe pawl and ratchet mechanism in an engaged configuration after theclip advancing assembly has advanced a proximal-most clip into theopposed jaws to thereby lock the trigger in an actuated position.

In one embodiment, the trigger can be movable in a first direction froma fully open position to a fully closed position, and a second directionfrom the fully closed position to the fully open position. The triggercan be limited to movement in only one of the first and seconddirections when the pawl and ratchet mechanism are in the engagedconfiguration. The trigger can be freely movable in both the first andsecond directions when the pawl and ratchet mechanism are in thedisengaged configuration. In some embodiments, the ratchet mechanism caninclude a series of teeth for engaging the pawl.

The clip advancing assembly can have many configurations. For example,the clip advancing assembly can include a feeder shoe and an advancerassembly. In some embodiments, the lockout mechanism can include a tangformed on the feeder shoe that is configured for locking engagement witha recess formed in the advancer assembly after the advancer assemblyadvances a proximal-most clip into the opposed jaws. An inferior surfaceof the feeder shoe can be in slidable engagement with a superior surfaceof the advancer assembly. In other embodiments, the opposed jaws can beconfigured to open and release a proximal-most clip before the lockoutmechanism locks the clip advancing assembly.

In another aspect, methods for advancing surgical clips are provided andcan include moving a trigger from an open-most position to a closed-mostposition to correspondingly advance a proximal-most clip of a pluralityof clips into opposed jaws of a clip applier. The method can furtherinclude releasing the trigger such that the trigger is locked in anactuated position between the open-most and closed-most positions toprevent the trigger from being moved to the open-most position. A tangformed on a feeder shoe can be engaged by a recess formed in an advancerassembly to lock the trigger. In some embodiments, moving the triggerfrom the open-most position to the closed-most position can move theadvancer assembly distally over the feeder shoe to advance theproximal-most clip into the opposed jaws of the clip applier.Furthermore, releasing the trigger can move the advancer assemblyproximally over the feeder shoe until the recess in the advancerassembly engages the tang on the feeder shoe. The method can alsoinclude releasing the proximal-most clip from the opposed jaws of theclip applier before the trigger is locked in an actuated positionbetween the open-most and closed-most positions to prevent the triggerfrom being moved to the open-most position.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1A is a side view of one exemplary embodiment of a surgical clipapplier;

FIG. 1B is an exploded view of the surgical clip applier shown in FIG.1A;

FIG. 2A is a top view of a jaw retainer assembly of the surgical clipapplier shown in FIG. 1A;

FIG. 2B is a bottom view of the jaw retainer assembly shown in FIG. 2A;

FIG. 2C is a side view of the jaw retainer assembly shown in FIG. 2B;

FIG. 2D is a cross-sectional view of the jaw retainer assembly shown inFIG. 2C taken across line D-D;

FIG. 3A is a top view of a feeder shoe for use with the jaw retainerassembly shown in FIGS. 2A-2D;

FIG. 3B is a bottom view of the feeder shoe shown in FIG. 3A;

FIG. 3C is a perspective view of another embodiment of a feeder shoe foruse with the jaw retainer assembly shown in FIGS. 2A-2D;

FIG. 3D is a perspective view of the feeder shoe of FIG. 3C;

FIG. 4A is a side perspective view of a feed bar that is configured toadvance the feeder shoe of FIGS. 3A and 3B through the jaw retainerassembly shown in FIGS. 2A-2D;

FIG. 4B is a side view of the proximal end of the feed bar shown in FIG.4A and the proximal end of the jaw retainer shaft shown in FIGS. 2A and2B, showing the feed bar in a proximal-most position;

FIG. 4C is a side view of the feed bar and jaw retainer shaft shown inFIG. 4B, showing the feed bar in a distal-most position;

FIG. 4D is a side view of another embodiment of a proximal end of a feedbar shown in connection with the proximal end of the jaw retainer shaftshown in FIGS. 2A and 2B, showing the feed bar in the proximal-mostposition;

FIG. 4E is a side view of the feed bar and jaw retainer shaft shown inFIG. 4D, showing the feed bar in a distal-most position;

FIG. 4F is a side view of yet another embodiment of a proximal end of afeed bar shown in connection with the proximal end of the jaw retainershaft shown in FIGS. 2A and 2B, showing the feed bar in theproximal-most position;

FIG. 4G is a side view of the feed bar and jaw retainer shaft shown inFIG. 4F, showing the feed bar in an intermediate position;

FIG. 4H is a side view of the feed bar and jaw retainer shaft shown inFIG. 4F, showing the feed bar in a distal-most position;

FIG. 4I is perspective view of another embodiment of a feed bar that isconfigured to advance the feeder shoe of FIGS. 3C and 3D through the jawretainer assembly shown in FIGS. 2A-2D;

FIG. 5A is a side perspective view of an advancer that is configured tocouple to a distal end of the feed bar shown in FIG. 4A;

FIG. 5B is a side perspective view of another embodiment of an advancerthat is configured to couple to a distal end of the feed bar shown inFIG. 4A;

FIG. 5C is a perspective view of still another embodiment of an advancerthat is configured to couple to a distal end of the feed bar shown inFIG. 4I;

FIG. 5D is another perspective view of the advancer of FIG. 5C;

FIG. 5E is a perspective view of the feed bar of FIG. 4I and theadvancer of FIGS. 5C and 5D mated together;

FIG. 6A is a cross-sectional view of a clip advancing assembly, whichincludes the jaw retainer assembly shown in FIGS. 2A-2D, the feeder shoeshown in FIGS. 3A-3B, and the feed bar shown in FIG. 4A, showing thefeed bar in an initial, proximal position relative to the clip track ofthe jaw retainer assembly;

FIG. 6B is a cross-sectional view of the clip advancing assembly shownin FIG. 6A, showing the feed bar moved in a distal direction;

FIG. 6C is a cross-sectional view of the clip advancing assembly shownin FIG. 6B, showing the feed bar moved further distally, thereby movingthe feeder shoe and a clip supply disposed distally of the feeder shoein a distal direction;

FIG. 6D is a cross-sectional view of the clip advancing assembly shownin FIG. 6C, showing the feed bar returned to the initial, proximalposition, shown in FIG. 6A, while the feeder shoe and clip supply remainin the advanced position shown in FIG. 6C;

FIG. 6E is a bottom perspective view of the advancer shown in FIG. 5Adisposed within the clip track of the jaw retainer assembly shown inFIGS. 2A-2D, showing the advancer in a proximal-most position;

FIG. 6F is a bottom perspective view of the advancer shown in FIG. 6E,showing the advancer in a distal-most position after advancing a clipinto the jaws of the surgical clip applier;

FIG. 6G is a perspective view of one embodiment of a stop mechanism forindicating to a user that a clip supply of an exemplary clip applier isdepleted;

FIG. 7 is a side perspective view of a pair of jaws of the surgical clipapplier shown in FIG. 1A;

FIG. 8 is a side perspective view of a cam for use with the jaws shownin FIG. 7;

FIG. 9 is a top perspective view of a push rod that is adapted to coupleto the cam shown in FIG. 8 for moving the cam relative to the jaws shownin FIG. 7;

FIG. 10A is a top view of the cam shown in FIG. 8 coupled to the jawsshown in FIG. 7, showing the cam in an initial position and the jawsopen;

FIG. 10B is a top view of the cam shown in FIG. 8 coupled to the jawsshown in FIG. 7, showing the cam advanced over the jaws and the jaws ina closed position;

FIG. 11A is a top perspective view of a tissue stop that is adapted tocouple to a distal end of the clip track of the jaw retainer assemblyshown in FIGS. 2A-2D;

FIG. 11B is a top perspective view of another embodiment of a tissuestop having a ramp formed thereon for guiding a clip into the jaws andstabilizing the clip during clip formation;

FIG. 11C is a side view of the tissue stop shown in FIG. 11B;

FIG. 11D is an enlarged view of the tissue stop shown in FIGS. 11B and11C;

FIG. 11E is a perspective view of another embodiment of a tissue stopthat is adapted to couple to a distal end of the clip track of the jawretainer assembly shown in FIGS. 2A-2D;

FIG. 11F is another perspective view of the tissue stop of FIG. 11E;

FIG. 12A is a top view of a distal end of the surgical clip appliershown in FIG. 1A showing the tissue stop of FIG. 11A positioned betweenthe jaws of FIG. 7;

FIG. 12B is perspective view of the advancer of FIG. 5C advancing a clipover the tissue stop of FIG. 11E;

FIG. 12C is a perspective view of the advancer of FIG. 5C in a distalposition on the tissue stop of FIG. 11E;

FIG. 12D is a perspective view of the advancer of FIG. 5C deflectingunder a distal-most clip within a channel formed in the tissue stop ofFIG. 11E;

FIG. 12E is a perspective view of the advancer of FIG. 5C in a proximalposition on the tissue stop of FIG. 11E;

FIG. 13 is a side, partially cross-sectional view of the handle portionof the surgical clip applier shown in FIG. 1A;

FIG. 14 is a side perspective view of a trigger insert of the surgicalclip applier shown in FIG. 1A;

FIG. 15A is a side perspective view of one half of a feed bar coupler ofthe surgical clip applier shown in FIG. 1A;

FIG. 15B is a side perspective view of the other half of the feed barcoupler shown in FIG. 15A;

FIG. 16 is a top perspective view of a flexible link that forms part ofa clip advancing assembly of the surgical clip applier shown in FIG. 1A;

FIG. 17A is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 1A, showing a clipadvancing assembly in an initial position;

FIG. 17B is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 17A, showing the clipadvancing assembly partially actuated;

FIG. 17C is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 17B, showing the clipadvancing assembly fully actuated;

FIG. 17D is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 17A, showing a clipforming assembly actuated;

FIG. 18 is a side view of a closure link roller that forms part of aclip forming assembly of the surgical clip applier shown in FIG. 1A;

FIG. 19 is a top perspective view of a closure link that couples to theclosure link roller shown in FIG. 18 to form part of a clip formingassembly of the surgical clip applier shown in FIG. 1A;

FIG. 20A is a top perspective view of a closure link coupler thatcouples to the closure link shown in FIG. 19 and that also forms part ofthe clip forming assembly of the surgical clip applier shown in FIG. 1A;

FIG. 20B is a bottom view of the closure link coupler shown in FIG. 20Acoupled to the push rod of FIG. 9 and having one embodiment of a biasingelement disposed therein;

FIG. 20C is a bottom view of the closure link shown in FIG. 20A coupledto the push rod of FIG. 9 and having another embodiment of a biasingelement disposed therein;

FIG. 20D is a chart showing the amount of force required to displace thebiasing element shown in FIG. 20B;

FIG. 20E is a side view of another embodiment of a portion of a closurelink coupler having ridges formed therein;

FIG. 21A is an enlarged side perspective view of an anti-backupmechanism of the surgical clip applier shown in FIG. 1A;

FIG. 21B is a perspective view of a pawl mechanism of the anti-backupmechanism shown in FIG. 21A;

FIG. 22A is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 1A, showing theanti-backup mechanism in an initial position;

FIG. 22B is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 22A, showing theanti-backup mechanism in a partially actuated position;

FIG. 22C is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 22B, showing theanti-backup mechanism in a fully actuated position;

FIG. 22D is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 22C, showing theanti-backup mechanism returning to an initial position;

FIG. 22E is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 22D, showing theanti-backup mechanism returned to the initial position;

FIG. 22F is a perspective view of one embodiment of a compression springfor biasing the closure link coupler of FIG. 20A;

FIG. 22G is a perspective view of the compression spring of FIG. 22F;

FIG. 23A is an exploded view of an overload mechanism of the surgicalclip applier shown in FIG. 1A;

FIG. 23B is a partially cross-sectional view of the overload mechanismshown in FIG. 23A, showing the closure link roller first coming intocontact with the profile link;

FIG. 23C is a partially cross-sectional view of the overload mechanismshown in FIG. 23B, showing the closure link roller applying a force tothe profile link causing the profile link to pivot;

FIG. 23D is a perspective view of another embodiment of an overloadmechanism for use with a surgical clip applier;

FIG. 24A is a side perspective view of a clip quantity indicator wheelof the surgical clip applier shown in FIG. 1A;

FIG. 24B is a side view of a clip quantity indicator wheel shown in FIG.24A;

FIG. 25 is a top perspective view of a clip quantity actuator for usewith the clip quantity indicator wheel shown in FIG. 24;

FIG. 26A is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 1A, showing movementof the clip quantity actuator of FIG. 25 and the clip quantity indicatorwheel of FIG. 24;

FIG. 26B is a side, partially cross-sectional view of a portion of thehandle of the surgical clip applier shown in FIG. 26A, showing furthermovement of the clip quantity actuator of FIG. 25 and the clip quantityindicator wheel of FIG. 24; and

FIG. 27A is a side view illustration showing another embodiment of afeeder shoe having a pre-formed A-shaped bend formed therein andconfigured to create friction between the feeder shoe and the cliptrack;

FIG. 27B is a side view illustration of another embodiment of a feedershoe having a pre-formed V-shaped bend formed therein and configured tocreate friction between the feeder shoe and the clip track;

FIG. 28A is a perspective top view of a portion of a clip track havingsurface protrusions formed therein and configured to create frictionbetween with the feeder shoe according to another embodiment of theinvention;

FIG. 28B is perspective end view of another embodiment of a feeder shoehaving a tang formed thereon and adapted to engage the surfaceprotrusions formed in the clip track shown in FIG. 28A;

FIG. 29A is a bottom perspective view of another embodiment of a feedershoe having a holdback lip formed on a tang that is adapted to engage acorresponding groove formed in a feed bar;

FIG. 29B is a top perspective view of another embodiment of a feed barhaving a catch groove formed therein and adapted to be engaged by theholdback lip formed on the tang of the feeder shoe shown in FIG. 29A;and

FIG. 29C is a side cross-sectional view of the feeder shoe of FIG. 29Adisposed within and engaging the feed bar of FIG. 29B.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally provides a surgical clip applier andmethods for using a surgical clip applier to apply surgical clips to avessel, duct, shunt, etc., during a surgical procedure. An exemplarysurgical clip applier can include a variety of features to facilitateapplication of a surgical clip, as described herein and illustrated inthe drawings. However, a person skilled in the art will appreciate thatthe surgical clip applier can include only some of these features and/orit can include a variety of other features known in the art. Thesurgical clip applier described herein is merely intended to representcertain exemplary embodiments.

FIG. 1A illustrates one exemplary surgical clip applier 10. As shown,the clip applier 10 generally includes a housing 12 having a stationaryhandle 14 and a movable handle or trigger 16 that is pivotally coupledto the housing 12. An elongate shaft 18 extends from the housing 12 andit includes a pair of opposed jaws 20 formed on a distal end thereof forcrimping a surgical clip. The elongate shaft 18 can be rotatably coupledto the housing 12, and it can include a rotation knob 22 for rotatingthe shaft 18 relative to the housing 12. FIG. 1B illustrates an explodedview of the surgical clip applier 10 shown in FIG. 1A, and the variouscomponents will be described in more detail below.

FIGS. 2A-12 illustrate exemplary embodiments of the various componentsof the shaft 18 of the surgical clip applier 10. In general, referringto FIG. 1B, the shaft 18 includes an outer tube 24 that houses the shaftcomponents, which can include a jaw retaining assembly 26 having a jawretainer shaft 28 with a clip track 30 and a push rod channel 32 formedthereon. The jaws 20 can be configured to mate to a distal end of theclip track 30. The shaft assembly 18 can also include a clip advancingassembly, which in one exemplary embodiment can include a feeder shoe 34that is adapted to be slidably disposed within the clip track 30 toadvance a series of clips 36 positioned therein, and a feed bar 38 thatis adapted to drive the feeder shoe 34 through the clip track 30. Thefeed bar 38 can include an advancer assembly 40 that is adapted to mateto a distal end thereof for advancing a distal-most clip into the jaws20. The shaft assembly 18 can also include a clip forming or cammingassembly, which in one exemplary embodiment can include a cam 42 that isadapted to slidably mate to the jaws 20, and a push rod 44 that cancouple to the cam 42 to move the cam 42 relative to the jaws 20. Theshaft assembly can also include a tissue stop 46 that can mate to adistal end of the clip track 30 for facilitating positioning of the jaws20 relative to a surgical site.

The various components of one exemplary clip advancing assembly areshown in more detail in FIGS. 2A-5. Referring first to FIGS. 2A-2D, thejaw retaining assembly 26 is shown and it includes an elongate,substantially planar jaw retainer shaft 28 having a proximal end 28 athat mates to the outer tube 24, and a distal end 28 b that is adaptedto mate to the jaws 20. While a variety of techniques can be used tomate the proximal end 28 a of the jaw retainer shaft 28 to the outertube 24, in the illustrated embodiment the proximal end 28 a includesteeth 31 formed on opposed sides thereof that are adapted to be receivedwithin corresponding holes or openings (not shown) formed in the outertube 24, and a cut-out 29 formed therein that allows the opposed sidesof the proximal end 28 a to deflect or to form a spring. In particular,the cut-out 29 allows the opposed sides of the proximal end 28 a of thejaw retainer shaft 28 to be compressed toward one another when the jawretainer shaft 28 is inserted in the outer tube 24. Once the teeth 31are aligned with the corresponding openings in the outer tube 24, theproximal end 28 a of the jaw retainer shaft 28 will return to itsoriginal, uncompressed configuration thereby causing the teeth 31 toextend into the corresponding openings to engage the outer 24. As willbe discussed in more detail below with respect to FIG. 4A, the devicecan also include a feature to prevent compression of the opposed sidesof the proximal end 28 a of the jaw retainer shaft 28 during use of thedevice to prevent accidental disengagement of the teeth 31 from theouter tube 24.

A variety of techniques can also be used to mate the distal end 28 b ofthe jaw retainer shaft 28 to the jaws 20, however in the illustratedembodiment the distal end 28 b of the jaw retainer shaft 28 includesseveral cut-outs or teeth 78 formed therein for mating withcorresponding protrusions or teeth 94 formed on the jaws 20, which willbe discussed in more detail below with respect to FIG. 7. The teeth 78allow a proximal portion of the jaws 20 to be substantially co-planarwith the jaw retainer shaft 28.

The jaw retaining assembly 26 can also include a push rod channel 32formed thereon for slidably receiving the push rod 44, which is used toadvanced the cam 42 over the jaws 20, as will be discussed in moredetail below. The push rod channel 32 can be formed using a variety oftechniques, and it can have any shape and size depending on the shapeand size of the push rod 44. As shown in FIG. 2D, the push rod channel32 is fixedly attached, e.g., by welding, to a superior surface of theretainer shaft 28, and it has a substantially rectangular shape anddefines a pathway 32 a extending therethrough. The push rod channel 32can also extend along all or only a portion of the retainer shaft 28. Aperson skilled in the art will appreciate that the jaw retainingassembly 26 does not need to include a push rod channel 32 forfacilitating movement of the push rod 44 within the elongate shaft 18 ofthe surgical clip applier 10.

As is further shown in FIGS. 2A-2D, the jaw retaining assembly 26 canalso include a clip track 30 mated thereto or formed thereon. The cliptrack 30 is shown mated to an inferior surface of the jaw retainer shaft28, and it extends distally beyond the distal end 28 b of the jawretainer shaft 28 to allow a distal end 30 b of the clip track 30 to besubstantially aligned with the jaws 20. In use, the clip track 30 isconfigured to seat at least one, and preferably a series, of clipstherein. Accordingly, the clip track 30 can include opposed side rails80 a, 80 b that are adapted to seat opposed legs of one or more clipstherein, such that the legs of the clips are axially aligned with oneanother. In an exemplary embodiment, the clip track 30 can be configuredto seat about twenty clips that are pre-disposed within the clip track30 during manufacturing. A person skilled in the art will appreciatethat the shape, size, and configuration of the clip track 30 can varydepending on the shape, size, and configuration of clips, or otherclosure devices such as staples, adapted to be received therein.Moreover, a variety of other techniques can be used, instead of a cliptrack 30, to retain a clip supply with the elongate shaft 18.

The clip track 30 can also include several openings 30 c formed thereinfor receiving a tang 82 a formed on a feeder shoe 34 adapted to bedisposed within the clip track 30, as will be discussed in more detailbelow. In an exemplary embodiment, the clip track 30 includes a quantityof openings 30 c that corresponds to at least the number of clipsadapted to be pre-disposed within the device 10 and applied during use.The openings 30 c are preferably equidistant from one another to ensurethat the tang 82 a on the feeder shoe 34 engages an opening 30 c eachtime the feeder shoe 34 is advanced. While not shown, the clip track 30can include detents, rather than openings 30 c, or it can include otherfeatures that allow the clip track 30 to engage the feeder shoe 34 andprevent proximal movement, yet allow distal movement, of the feeder shoe34. The clip track 30 can also include a stop tang 118 formed thereon,as shown in FIG. 2B, that is effective to be engaged by a correspondingstop tang formed on the feeder shoe 34 to prevent movement of the feedershoe 34 beyond a distal-most position, as will be discussed below. Thestop tang 118 can have a variety of configurations, but in one exemplaryembodiment it is in the form of two adjacent tabs that extend toward oneanother to enclose a portion of the clip track, thus allowing clips topass therethrough.

An exemplary feeder shoe 34 is shown in more detail in FIGS. 3A and 3B,and it can be adapted to directly drive clips through the clip track 30.While the feeder shoe 34 can have a variety of configurations, and avariety of other techniques can be used to drive clips through the cliptrack 30, in an exemplary embodiment the feeder shoe 34 has a generallyelongate shape with proximal and distal ends 34 a, 34 b. The distal end34 b can be adapted to cradle the proximal-most clip in the clip track30 to push the clip(s) through the clip track 30. In the illustratedexemplary embodiment, the distal end 34 b is substantially v-shaped forseating a v-shaped bight portion of a clip. The distal end 34 b alsoincludes a rectangular-shaped notch 34 c formed therein for allowing theadvancer 40 to engage a distal-most clip and advance it into the jaws20, as will be discussed in more detail below. The distal end 34 b can,of course, vary depending on the configuration of the clip, or otherclosure mechanism, being used with the device 10.

In another exemplary embodiment, the feeder shoe 34 can also includefeatures to facilitate distal movement of the feeder shoe 34 within theclip track 30, and to substantially prevent proximal movement of thefeeder shoe 34 within the clip track 30. Such a configuration willensure advancement and proper positioning of the clips within the cliptrack 30, thus allowing a distal-most clip to be advanced between thejaws 20 with each actuation of the trigger 16, as will be discussed inmore detail below. In the illustrated exemplary embodiment, the feedershoe 34 includes a tang 82 a formed on a superior surface 34 s thereofand angled proximally for engaging one of the openings 30 c formed inthe clip track 30. In use, the angle of the tang 82 a allows the feedershoe 34 to slide distally within the clip track 30. Each time the feedershoe 34 is advanced, the tang 82 a will move in a distal direction fromone opening 30 c to the next opening 30 c in the clip track 30. Theengagement of the tang 82 a with the opening 30 c in the clip track 30will prevent the feeder shoe 34 from moving proximally to return to theprevious position, as will be described in more detail below.

In order to facilitate distal movement of the feeder shoe 34 within theclip track 30, the feeder shoe 34 can also include a tang 82 b formed onthe inferior surface 34 i thereof, as shown in FIG. 3B, for allowing thefeeder shoe 34 to be engaged by the feed bar 38 (FIG. 4A) as the feedbar 38 is moved distally. The inferior tang 82 b is similar to thesuperior tang 82 a in that it can be angled proximally. In use, eachtime the feed bar 38 is moved distally, a detent 84 formed in the feedbar 38 can engage the inferior tang 82 b and move the feeder shoe 34distally a predetermined distance within the clip track 30. The feed bar38 can then be moved proximally to return to its initial position, andthe angle of the inferior tang 82 b will allow the tang 82 b to slideinto the next detent 84 formed in the feed bar 38. As previously noted,a variety of other features rather than tangs 82 a, 82 b and openings 30c or detents 84 can be used to control movement of the feeder shoe 34within the clip track 30.

As previously mentioned, the feeder shoe 34 can also include a stopformed thereon that is adapted to stop movement of the feeder shoe 34when the feeder shoe 34 is in the distal-most position and there are noclips remaining in the device 10. While the stop can have a variety ofconfigurations, FIGS. 3A and 3B illustrate a third tang 82 c formed onthe feeder shoe 34 and extending in an inferior direction for engagingthe stop tang 118 (FIG. 2B) formed on the clip track 30. The third tang82 c is positioned such that it will engage the stop tang 118 on theclip track 30 when the feeder shoe 34 is in a distal-most position,thereby preventing distal movement of the feeder shoe 34 and the feedbar 38 when the clip supply is depleted.

In another embodiment, the surgical clip applier can have a stopmechanism that can indicate to a user when a clip supply of the surgicalclip applier is depleted. The stop mechanism can, for example, preventthe user from fully opening a trigger of the surgical clip applier tothereby indicate that the last clip has been applied. This prevents theuser from continuing to attempt to apply clips in the belief that clipsremain in the clip supply. The stop mechanism can have manyconfigurations, but in an exemplary embodiment the stop mechanism isconfigured to lock the clip advancing assembly of the surgical clipapplier in a fixed position after a proximal-most clip has been advancedinto opposed jaws of the clip applier. This is in turn effective to lockthe trigger 16, which is operatively associated with the clip advancingassembly, in a fixed position. Thus, as a user attempts to release thetrigger 16 of the clip applier and return it to its open position, thelocked advancer and feed bar prevent the trigger from returning to itsopen position, thereby indicating to the user that the clip supply isdepleted.

While the stop mechanism can have any configuration and can be formed atvarious locations on the device, in one embodiment the stop mechanism isin the form of an engagement feature formed on the feeder shoe and thefeed bar. FIGS. 3C and 3D illustrate one exemplary embodiment of afeeder shoe 34″′ having an engagement feature formed thereon for matingwith a corresponding engagement feature on the feed bar, as will bediscussed in more detail below. Similar to the previous embodiment, theillustrated feeder shoe 34″′ has a generally elongate shape withproximal and distal ends 34 a′, 34 b′. The distal end 34 b′ is adaptedto cradle the proximal-most clip in the clip track 30 to push theclip(s) through the clip track 30. In this embodiment, the distal end 34b′ is substantially v-shaped for seating a v-shaped bight portion of aclip. The distal end 34 b′ can also include a rectangular-shaped notch34 c′ formed therein for allowing the advancer 40, 40″ to engage adistal-most clip and advance it into the jaws 20, as will be discussedin more detail below. The distal end 34 b′ can, of course, varydepending on the configuration of the clip, or other closure mechanism,being used with the device 10.

The illustrated feeder shoe 34″′ can also include a number of features,such as tangs similar to those discussed above with respect to thefeeder shoe 34 shown in FIGS. 3A and 3B, to facilitate distal movementof the feeder shoe 34″′ within the clip track 30, and to substantiallyprevent proximal movement of the feeder shoe 34″′ within the clip track30. Such a configuration will ensure advancement and proper positioningof the clips within the clip track 30, thus allowing a distal-most clipto be advanced between the jaws 20 with each actuation of the trigger16, as will be discussed in more detail below. For example, one or moretangs can be provided on the feeder shoe 34″′ to engage the clip track30. The tangs can generally have a rectangular shape and can be formedby cutting three sides of a rectangle from the feeder shoe 34″′ anddeflecting the rectangle away from the feeder shoe 34′ so as to form asnag tab. Tangs that are angled proximally can be spaced apart from asuperior or inferior surface of the feeder shoe 34″′ at their proximalend to form a catch that will engage the clip track 30 when the feedershoe 34″′ is moved proximally. Likewise, tangs that are angled distallycan be spaced apart from a superior or inferior surface of the feedershoe 34″′ at their distal end to form a catch that will engage the cliptrack 30 when the feeder shoe 34″′ is moved distally. In the illustratedexemplary embodiment, the feeder shoe 34″′ includes a tang 82 a′ thatprotrudes above a superior surface 34 s′ of the feeder shoe 34″′ andthat is angled proximally for engaging one of the openings 30 c formedin the clip track 30. In use, the angle of the tang 82 a′ allows thefeeder shoe 34″′ to slide distally within the clip track 30. Each timethe feeder shoe 34″′ is advanced, the tang 82 a′ will move in a distaldirection from one opening 30 c to the next opening 30 c in the cliptrack 30 (shown in FIG. 6A). The engagement of the tang 82 a′ with theopening 30 c in the clip track 30 will prevent the feeder shoe 34″′ frommoving proximally to return to the previous position, as will bedescribed in more detail below.

In order to facilitate distal movement of the feeder shoe 34″′ withinthe clip track 30, the feeder shoe 34″′ can also include a tang 82 b′that protrudes below the inferior surface 34 i′ of the feeder shoe 34″′,as shown in FIG. 3D, for allowing the feeder shoe 34″′ to be engaged bya feed bar 38′ as the feed bar 38′ is moved distally. The inferior tang82 b′ is similar to the superior tang 82 a′ in that it can be angledproximally. In use, each time the feed bar 38′ is moved distally, adetent 84 formed in the feed bar 38′ can engage the inferior tang 82 b′and move the feeder shoe 34″′ distally a predetermined distance withinthe clip track 30. The feed bar 38′ can then be moved proximally toreturn to its initial position, and the angle of the inferior tang 82 b′will allow the tang 82 b′ to slide into the next detent 84 formed in thefeed bar 38′. As previously noted, a variety of other features ratherthan tangs 82 a′, 82 b′ and openings 30 c or detents 84 can be used tocontrol movement of the feeder shoe 34″′ within the clip track 30.

The feeder shoe 34″′ can also include a stop formed thereon that isadapted to stop distal movement of the feeder shoe 34″′ when the feedershoe 34″′ is in the distal-most position and there are no clipsremaining in the device 10. While the stop can have a variety ofconfigurations, FIGS. 3C and 3D illustrate a third tang 82 c′ formed onthe feeder shoe 34″′ that protrudes below the inferior surface and thatis angled for engaging the stop tang 118 (FIG. 2B) formed on the cliptrack 30. The third tang 82 c′ is positioned such that it will engagethe stop tang 118 on the clip track 30 when the feeder shoe 34″′ is in adistal-most position, thereby preventing distal movement of the feedershoe 34″′ and the feed bar 38 when the clip supply is depleted.

The feeder shoe 34″′ can further include a stop mechanism that isadapted to lock an advancer 40″ and the feed bar 38′, described in moredetail below, in a fixed position after the advancer 40″ advances theproximal-most clip into the jaws 20. Such a stop mechanism can providetactile feedback to a user to ensure that the user is aware that theclip supply is depleted.

While the stop mechanism can have many configurations, in the embodimentillustrated in FIGS. 3C and 3D, the feeder shoe 34″′ includes a fourthtang 82 d′ that extends below the inferior surface and that is angleddistally. A proximal portion 83 of the tang 82 d′ is connected with thefeeder shoe 34″′ while a distal portion 85 is not connected with thefeeder shoe 34″′ and is spaced a distance apart from the inferiorsurface. The tang 82 d′ is positioned to engage a recess 51 formed inthe advancer 40′ and the feed bar 38′ to thereby prevent the advancer40″ and the feed bar 38′ from moving proximally back to their startingposition, as will be described in more detail below.

FIG. 4A illustrates an exemplary feed bar 38 for driving the feeder shoe34 through the clip track 30 of the jaw retaining assembly 26. As shown,the feed bar 38 has a generally elongate shape with proximal and distalends 38 a, 38 b. The proximal end 38 a of the feed bar 38 a can beadapted to mate to a feed bar coupler 50 (FIG. 1B), which will bediscussed in more detail below. The feed bar coupler 50 can mate to afeed link 52 that is effective, upon actuation of the trigger 16, toslidably move the feed bar 38 in a distal direction within the elongateshaft 18. The distal end 38 b of the feed bar 38 b can be adapted tomate to an advancer 40, 40′, exemplary embodiments of which are shown inFIGS. 5A and 5B, that is effective to drive a distal-most clip disposedwithin the clip track 30 into the jaws 20, which will be discussed inmore detail below.

As previously mentioned, the proximal end 38 a of the feed bar 38 caninclude a feature to prevent compression of the opposed sides of theproximal end 28 a of the jaw retainer shaft 28 (FIGS. 2A and 2B) duringuse of the device to prevent accidental disengagement of the teeth 31from the outer tube 24. In one exemplary embodiment, shown FIGS. 4A-4C,the proximal end 38 a of the feed bar 38 can include a protrusion 39formed thereon that is adapted to extend into the opening 29 formed inthe proximal end 28 a of the jaw retainer shaft 28. When the feed bar 38is in a proximal-most position (i.e., when the trigger 16 is in an openposition), the protrusion 39 will be positioned at the proximal end ofthe opening 29, as shown in FIG. 4B, allowing the proximal end 28 a ofthe jaw retainer shaft 28 to compress to allow the shaft 28 to slideinto the outer tube 24. When the feed bar 38 is in a distal-mostposition (i.e., when the trigger 16 is in at least a partially closedposition), the protrusion 39 will be positioned at an intermediatelocation adjacent to the teeth 31 as shown in FIG. 4C, to preventcompression of the proximal end 28 a of the jaw retainer shaft 28. Thisis particularly advantageous during use of the device, as the protrusion39 will prevent accidental disengagement of the jaw retainer shaft 28from the outer tube 24 during use of the device. While FIGS. 4A-4Cillustrate a protrusion 39 having a rectangular cross-sectional shapewith rounded edges, the protrusion 39 can have a variety of other shapesand sizes. For example, as shown in FIGS. 4D and 4E, the protrusion 39′has a cross-sectional shape that is somewhat triangular with a taperingend that is adapted to extend between the teeth 31 to further ensurethat the proximal end 28 a of the jaw retainer shaft 28 can not becompressed during use of the device. More than one protrusion can alsobe used. For example, FIGS. 4F-4H illustrate another embodiment in whichthe proximal end 38 a′ of the feed bar 38 includes two protrusions 39 a,39 b formed thereon and spaced a distance apart from one another. Thetwo protrusions 39 a, 39 b will prevent compression of the proximal end28 a of the jaw retainer shaft 28 when the feed bar 38 is in aproximal-most position, as shown in FIG. 4F, and when the feed bar 38 isin a distal-most position, as shown in FIG. 4H. Compression of theproximal end 28 a of the jaw retainer shaft 28 can only occur when thefeed bar 38 is at an intermediate position such that the teeth 31 arepositioned between the protrusions 39 a, 39 b, as shown in FIG. 4G.

As was also previously mentioned, the feed bar 38 can include one ormore detents 84 formed therein for engaging the inferior tang 82 bformed on the feeder shoe 34. The quantity of detents 84 can vary, butin an exemplary embodiment the feed bar 38 has a quantity of detents 84that corresponds to or is greater than a quantity of clips adapted to bedelivered by the device 10, and more preferably it has one more detent84 than the quantity of clips adapted to be delivered by the device 10.By way of non-limiting example, the feed bar 38 can include eighteendetents 84 formed therein for delivering seventeen clips that arepre-disposed within the clip track 30. Such a configuration allows thefeed bar 38 to advance the feeder shoe 34 seventeen times, therebyadvancing seventeen clips into the jaws 20 for application. The detents84 are also preferably equidistant from one another to ensure that thefeeder shoe 34 is engaged and advanced by the feed bar 38 each time thefeed bar 38 is advanced.

The feed bar 38 can also include a feature to control the amount ofmovement of the feed bar 38 relative to the clip track 30. Such aconfiguration will ensure that the feeder shoe 34 is advanced apredetermined distance each time the trigger 16 is actuated, therebyadvancing only a single clip into the jaws 20. While a variety oftechniques can be used to control the distal of movement of the feed bar38, in an exemplary embodiment the feed bar 38 can include a protrusion86 formed thereon that is adapted to be slidably received within acorresponding slot 88 (FIG. 2B) formed in the jaw retainer shaft 28. Thelength of the slot 88 is effective to limit movement of the protrusion86 therein, thus limiting movement of the feed bar 38. Accordingly, inuse the feed bar 38 can slide between a fixed proximal position and afixed distal position with respect to the clip track 30, therebyallowing the feed bar 38 to advance the feeder shoe 34 by apredetermined distance with each advancement of the feed bar 38.

FIG. 4I illustrates another exemplary embodiment of a feed bar 38′. Inthe illustrated embodiment, the feed bar 38′ is the same as theembodiment described in FIG. 4A except for its distal end 38 b′. Thedistal end 38 b′ can be configured to mate with the advancer 40″ thatwill be described in more detail below, and it can be used with thefeeder shoe 34′ described above. As noted above, the feeder shoe 34′ canhave a stop mechanism that is able to lock the advancer 40″ and the feedbar 38′ in place after a proximal-most clip is advanced into the jaws20. The stop mechanism can be, for example, a tang 82 d′ formed on thefeeder shoe 34′ that is adapted to engage a recess 51 a formed the feedbar 38′, as shown in FIG. 4I. The recess 51 a, in combination with therecess 51 b, is configured to catch and retain the tang 82 d′ as theadvancer 40″ and the feed bar 38′ are moved over the feeder shoe 34′.The recesses 51 a, 51 b can have any size as needed and can be formed onthe same side of the feed bar 38′ as the detents 84. In the illustratedembodiment, the recesses 51 a, 51 b are in the shape of a square andhave sidewalls configured for receiving the tang 82 d′ therebetween.Once engaged, the tang 82 d′ is unable to move out of the recesses 51 a,51 b thereby locking the advancer 40″ and the feed bar 38′ in a lockedposition. The feed bar 38′ can also include an elongated recess 57formed in its distal end 38 b′ for receiving the proximal end 53 of theadvancer 40″ so that the two components can be mated together asdescribed below.

FIG. 5A illustrates one exemplary embodiment of an advancer 40 that isadapted to mate to the distal end 38 b of the feed bar 38 and which iseffective to drive a distal-most clip from the clip track 30 into thejaws 20. A variety of techniques can be used to mate the advancer 40 tothe feed bar 38, but in the illustrated embodiment the proximal end 40 aof the advancer 40 is in the form of a female connector that is adaptedto receive the male connector formed on the distal end 38 b of the feedbar 38. The advancer 40 preferably fixedly mates to the feed bar 38,however it can optionally be integrally formed with the feed bar 38. Thedistal end 40 b of the feed bar 38 is preferably adapted to advance aclip into the jaws 20 and thus the distal end 40 b of the advancer 40can include, for example, a clip-pusher member 90 formed thereon. Theclip-pusher member 90 can have a variety of shapes and sizes, but in oneexemplary embodiment it has an elongate shape with a recess 92 formed inthe distal end thereof for seating the bight portion of a clip. Theshape of the recess 92 can vary depending on the particularconfiguration of the clip. The clip-pusher member 90 can also extend atan angle in a superior direction with respect to a longitudinal axis Aof the advancer 40. Such a configuration allows the clip-pusher member90 to extend into the clip track 30 to engage a clip, while theremainder of the advancer 40 extends substantially parallel to the cliptrack 30.

FIG. 5B illustrates another exemplary embodiment of a clip-pusher member90′ of an advancer 40′. In this embodiment, the clip-pusher member 90′is slightly more narrow and it has a small recess 92′ formed in thedistal-most end thereof. In use, the advancer 40 can engage and advanceonly the distal-most clip disposed within the clip track 30 into thejaws 20. This is due to the positioning of the feed bar 38, which isslidably movable between a fixed proximal and distal positions, aspreviously discussed.

FIGS. 5C and 5D illustrate still another exemplary embodiment of aclip-pusher member or distal tip 90″ of an advancer 40″. In thisembodiment, the clip-pusher member or distal tip 90″ has been modifiedto allow an apex of a surgical clip being advanced into the jaws to movein superior and inferior directions while still maintaining contact withthe apex of the surgical clip. In addition, and as noted above, theadvancer 40″ can include a recess 51 b formed near a proximal end 53thereof. The recess 51 b can have any size and shape as needed to catchand hold the tang 82 d′ formed on the feeder shoe 34′ such that theadvancer 40″, as well as the feed bar 38′ to which the advancer 40″ iscoupled, is locked in position and unable to move to an open positionafter a proximal-most clip is advanced into the jaws 20.

With regard to the distal tip 90″, in general, the distal tip 90″ has anelongate configuration with a proximal end 90 p″ that is coupled to abody portion or shaft 42″ of the advancer 40″. The shaft 42″ can havevarious shapes and sizes, but in the illustrated embodiment the shaft42″ has a generally planar configuration with superior and inferiorsurfaces 42 s″, 42 i″. The particular configuration of the shaft 42″,with the exception of the distal tip 90″, can be similar to theembodiments previously described herein. In an exemplary embodiment, thedistal tip 90″ and the shaft 42″ can be formed as a single integralcomponent, however each component can be formed from differentmaterials. For example, the distal tip 90″ can be formed from a metal,while the entire shaft 42″ or a portion of the shaft 42″ can be formedfrom a plastic that is integral to the feed bar 38 and is overmoldedonto the metal distal tip 90″. Regardless of the particular materialused, the distal tip 90″ is preferably formed from a flexible materialthat allows the tip 90″ to deflect in superior and inferior directionsrelative to the shaft 42″. In certain exemplary embodiments, the distaltip 90″ can be formed by punching a predetermined shape out of a planarsheet of metal, and then folding opposed sides of the shape together toform the tip as shown, with the inferior surface being hollow.

As indicated above, the distal tip 90″ can be configured to allow anapex of a surgical clip being advanced into the jaws by the tip to movein superior and inferior directions while still maintaining contact withthe apex of the clip. In other words, the distal tip 90″ can have aheight that is greater than a height of the apex, as measured in thesuperior/inferior direction (i.e., transverse to the longitudinal axisof the advancer 40″). This will allow the apex of the clip to slide upand down along the tip. In particular, as shown in FIG. 5D, adistal-facing surface 41 of the clip-pusher member 90″ can have a heightH, measured in a superior/inferior direction, that is greater than aheight (as measured in the same direction) of an apex of a clip pushedby the clip-pusher member 90″, as will be described in more detailbelow. The increased height can result from a distal biasing surface 43formed on an inferior surface of the tip 90″ and located adjacent to thedistal end 90 d″ of the tip 90″. The distal biasing surface 43 can be inthe form of a ramped portion or a surface feature. As further shown inFIGS. 5C and 5D, the distal tip 90″ can also include a proximal biasingsurface 45 formed on an inferior surface of the tip 90″ and locatedadjacent to the proximal end 90 p″ of the tip 90″. The two biasingsurfaces 43, 45 can be configured to interact with the tissue stop, aswill be described in detail below, and to thereby deflect in superiorand inferior directions relative to the tissue stop. The flexible orresilient material used to form the advancer tip 90″ can facilitaterepeated bending of the distal tip 90″. As further shown in FIGS. 5C and5D, a superior or top portion 47 of the clip-pusher member 90″ can besubstantially straight and can extend upward at an angle between theproximal end 90 p″ of the tip 90″ and the distal end 90 d″ of the tip90″. A person skilled in the art will appreciate that the particularconfiguration of the distal tip 90″ can vary depending on the desiredmovement of the tip during use.

FIG. 5E illustrates the advancer 40″ and the feed bar 38′ matedtogether. As shown, the distal end 53 of the advancer 40″ is disposedwithin the recess 57 formed in the feed bar 38′. The two can be matedtogether using any technique known in the art including, but not limitedto, press or interference fit, adhesives, fasteners, etc. The recesses51 a, 51 b can extend entirely through the proximal end 53 of theadvancer 40″, and it can extend into the distal end 38 b′ of the feedbar 38′.

FIGS. 6A-6F illustrate the clip advancing assembly in use, and inparticular FIGS. 6A-6D illustrate movement of the feed bar 38 within theclip track 30 to advance the feeder shoe 34 and clip supply 36, andFIGS. 6E-6F illustrate movement of the advancer 40 to advance adistal-most clip into the jaws 20. The components in the housing 12 thatare used to actuate the clip advancing assembly will be discussed inmore detail below.

As shown in FIG. 6A, in the resting position the feed bar 38 is in aproximal-most position such that the protrusion 86 is positionedproximally within the elongate slot 88 in the jaw retainer shaft 28. Thefeeder shoe 34 is disposed within the clip track 30 and, assuming thedevice 10 has not yet been used, the feeder shoe 34 is in aproximal-most position such that the superior tang 82 a on the feedershoe 34 is engaged with the proximal-most or first opening 30 c ₁ formedin the clip track 30 to prevent proximal movement of the feeder shoe 34,and the inferior tang 82 b on the feeder shoe 34 is positioned betweenthe first detent 84 ₁ and the second detent 84 ₂ in the feed bar 38,such that the inferior tang 82 b is biased in a superior direction bythe feed bar 38. The detents 84 in the feed bar are labeled sequentiallyas 84 _(k), 84 ₂, etc., and the openings 30 c in the clip track 30 arelabeled sequentially as 30 c ₁, 30 c ₂, etc. As is further shown in FIG.6A, a series of clips 36, labeled sequentially as 36 _(k), 36 ₂, . . .36 _(x) with 36 _(x) being the distal-most clip, are positioned withinthe clip track 30 distal of the feeder shoe 34.

Upon actuation of the trigger 16, the feed bar 38 is advanced distally,causing the protrusion 86 to slide distally within the slot 88. As thefeed bar 38 moves distally, the inferior tang 82 b on the feeder shoe 34will slide into the first detent 84 ₁ in the feed bar 38. Further distalmovement of the feed bar 38 will cause the first detent 84 ₁ to engagethe inferior tang 82 b, as shown in FIG. 6B, and to move the feeder shoe34 and clip supply 36 _(k), 36 ₂, etc. in a distal direction. As shownin FIG. 6C, when the protrusion 86 abuts the distal end of the elongateslot 88 in the jaw retainer shaft 28, the feed bar 38 is prevented fromfurther distal movement. In this position, the feeder shoe 34 hasadvanced a predetermined distance to advance the clip supply 36 _(k), 36₂, . . . 36 _(x) within the clip track 30 by a predetermined distance.The superior tang 82 a of the feeder shoe 34 has been advanced into thesecond opening 30 c ₂ in the clip track 30 to prevent proximal movementof the feeder shoe 34, and the inferior tang 82 b on the feeder shoe 34is still engaged by the first detent 84 ₁ in the feed bar 38.

Movement of the feed bar 38 from the initial, proximal-most position,shown in FIG. 6A, to the final, distal-most position, shown in FIG. 6C,will also advance the distal-most clip 36 _(x) into the jaws 20. Inparticular, as shown in FIG. 6E, distal movement of the feed bar 38 willcause the clip-pusher member 90 of the advancer 40, which is attached tothe distal end of the feed bar 38, to engage the distal-most clip 36_(x) disposed within the clip track 30 and to advance the clip 36 _(x)into the jaws 20, as shown in FIG. 6F. In an exemplary embodiment, theadvancer 40 will engage and initiate advancement of the distal-most clip36 _(x) prior to engaging and initiating advancement of the feeder shoe34. As a result the distal-most clip 36 _(x) will advance a distancethat is greater than a distance traveled by the feeder shoe 34. Such aconfiguration allows only the distal-most clip 36 _(x) to be advancedinto the jaws 20 without accidentally advancing an additional clip intothe jaws 20.

Once the clip 36 _(x) has been partially or fully formed, the trigger 16can be released to release the formed clip 36 _(x). Release of thetrigger 16 will also retract the feed bar 38 in a proximal directionuntil the protrusion 86 returns to the initial proximal-most positionwithin the elongate slot 88, as shown in FIG. 6D. As the feed bar 38 isretracted proximally, the feeder shoe 34 will not move proximally sincethe superior tang 82 a will engage the second opening 30 c ₂ in the cliptrack 30. The inferior tang 82 b will not interfere with proximalmovement of the feed bar 38, and once the feed bar 38 is in the initial,proximal-most position, as shown, the inferior tang 82 b will bepositioned between the second detent 84 ₂ and the third detent 84 ₃ inthe feed bar 38.

The process can be repeated to advance another clip into the jaws 20.With each actuation of the trigger 16, the inferior tang 82 b will beengaged by the next detent, i.e., detent 84 ₂ formed in the feed bar 38,the superior tang 82 a on the feeder shoe 34 will be moved distally intothe next opening, i.e., opening 30 c ₃ on the clip track 30, and thedistal-most clip will be advanced into the jaws 20 and released. Wherethe device 10 includes a predetermined amount of clips, e.g., seventeenclips, the trigger 16 can be actuated seventeen times. Once the lastclip has been applied, the stop, e.g., the third tang 82 c, on thefeeder shoe 34 can engage the stop tang 118 on the clip track 30 toprevent further distal movement of the feeder shoe 34.

As explained above, in another embodiment the clip applier can include astop mechanism that is effective to lock the trigger 16 in a partiallyopened position after the last clip is applied, thereby indicating to auser that the last clip has been applied. FIG. 6G illustrates use of astop mechanism formed between the feed bar 38′ of FIG. 4I and the feedershoe 34″′ of FIGS. 3C and 3D. In use, when the last clip is applied totissue, the stop mechanism can lock the advancer 40″ (shown in FIGS.5C-E) and feed bar 38′ in place relative to the feeder shoe 34″′ tothereby prevent the trigger 16 from opening to its starting position. Inparticular, as the feeder shoe 34″′ advances the proximal-most clip(i.e., the last clip remaining in the clip track) into position to beadvanced into the jaws 20, it moves into sliding engagement with theadvancer 40″. The trigger 16 can be actuated from its starting positionto cause the advancer 40″ to move the proximal-most clip into the jaws20. As the advancer 40″ and the feed bar 38′ move distally adjacent tothe feeder shoe 34″′ to move the proximal-most clip into the jaws 20,the recesses 51 a, 51 b move distally over the tang 82 d′. Movingdistally, the recesses 51 a, 51 b do not engage the tang 82 d′ becausethe tang 82 d′ is angled distally. As the trigger 16 is released,however, the advancer 40″ and the feed bar 38′ begin to move proximallyadjacent to the feeder shoe 34″′. Once the recesses 51 a, 51 b reach thetang 82 d′, the tang 82 d′ will extend into and engage the recesses 51a, 51 b to lock the advancer 40″ and the feed bar 38″ in a fixedposition, preventing further proximal movement. This engagement betweenthe recesses 51 a, 51 b and the tang 82 d′ preferably occurs prior tothe trigger being fully opened. In other words, engagement preferablyoccurs when the trigger 16 is in a partially opened position. Engagementbetween the feeder shoe 34″′ and the advancer 40″ and feed bar 38″ alsopreferably occurs when a pawl and ratchet mechanism associated with thetrigger is in a position in which the pawl is prevented from rotating,as will be discussed in more detail below. This will prevent furthermovement of the trigger 16 in either direction. Accordingly, theinability of the trigger to move in any direction will indicate to auser that the clip supply is depleted.

The feeder shoe 34, feed bar 38, and/or the clip track 30 can alsooptionally include features to prevent accidental or unintentionalmovement of the feeder shoe 34, for example during shipment of thedevice. This is particularly advantageous as migration of the feedershoe 34, particularly prior to first use of the device, can cause thedevice to malfunction. For example, if the feeder shoe 34 migratesdistally, the feeder shoe 34 will advance two clips into the jawssimultaneously, thereby resulting in delivery of two misformed clips.Accordingly, in an exemplary embodiment the feeder shoe 34, feed bar 38,and/or the clip track 30 can include an engagement mechanism and/or canbe configured to generate a frictional force therebetween that issufficient to resist movement, but that can be overcome by actuation ofthe trigger 16 to allow the feed bar to advance the feeder shoe 34through the clip track 30.

While various techniques can be used to prevent undesirable migration ofthe feeder shoe 34 within the clip track 30, FIGS. 27A-29C illustratevarious exemplary embodiments of techniques for creating friction or anengagement mechanism between the feeder shoe 34, feed bar 38, and/or theclip track 30. Referring first to FIG. 27A, one exemplary embodiment ofa feeder shoe 34′ is shown having a pre-formed cantilevered or bowedconfiguration in a free state (i.e., when the feeder shoe 34′ is removedfrom the clip track 30) such that the feeder shoe 34′ forms acantilevered spring when disposed within the clip track 30. Inparticular, a portion of the feeder shoe 34′ can include a bend 35′formed therein such that the opposed ends 34 a′, 34 b′ of the feedershoe 34′ are angled relative to one another. The bend 35′ can cause theheight h_(b) of the feeder shoe 34′ to be greater than the height of theclip track 30. While the height h_(b) can vary, in an exemplaryembodiment the bend 35′ is configured to increase a height of the feedershoe 34′ by an amount that is sufficient to create a frictional dragforce between the feeder shoe 34′ and the clip track 30, but that stillallows the feeder shoe 34′ to slide within the clip track 30 when thetrigger 16 is actuated. In an exemplary embodiment, the height of thefeeder shoe 34′ is increased at least about 30%, or more preferablyabout 40%. In use, the clip track 30 will force the feeder shoe 34′ intoa substantially planar configuration such that the feeder shoe 34′ isbiased against the clip track 30 when disposed therein. The bend 35′ ofthe feeder shoe 34′, as well as the terminal ends 34 a′, 34 b′ of thefeeder shoe 34′, will therefore apply a force to the clip track 30,thereby creating a frictional drag force between the feeder shoe 34′ andthe clip track 30. The frictional force will prevent the feeder shoe 34′from migrating relative to the clip track 30 unless the trigger 16 isactuated, in which case the force applied by the trigger 16 willovercome the frictional forces.

A person skilled in the art will appreciate that the bend 35′ can have avariety of configurations, and it can be formed anywhere along thelength of the feeder shoe 34′. In FIG. 27A the bend 35′ is formed at ornear the mid-portion of the feeder shoe 34′. The bend 35′ can alsoextend in various directions. While FIG. 27A illustrates the bend 35′extending in a direction perpendicular to the axis such that the bend35′ and the ends 34 a′, 34 b′ apply a force to the clip track 30, thebend 35′ can alternatively extend along a longitudinal axis of thefeeder shoe 34′ such that the feeder shoe 34′ applies a force to theopposed side rails 80 a, 80 b (FIG. 2D) of the clip track 30. The bend35′ can also angle the opposed ends 34 a′, 34 b′ in a downwarddirection, as shown in FIG. 27A, such that the feeder shoe 34′ issubstantially A-shaped, or alternatively the bend 35″ can angle theopposed ends 34 a″, 34 b″ in an upward direction, as shown in FIG. 27B,such that the feeder shoe 34″ is substantially V-shaped. The feeder shoe34′ can also include any number of bends formed therein. A personskilled in the art will appreciate that the particular configuration ofthe bend(s) can be modified based on the properties of the feeder shoe34′ and the clip track 30 to obtain a desired amount of frictional forcetherebetween.

FIGS. 28A and 28B illustrate another embodiment of a technique forcreating frictional forces between the feeder shoe and clip track. Inthis embodiment, the clip track 30′ and/or the feeder shoe 34 _(x) caninclude one or more surface protrusions formed thereon. As shown in FIG.28A, two surface protrusions 82 d ₁, 82 d ₂ are formed on the clip track30′. While the surface protrusions 82 d ₁, 82 d ₂ can be formed atvarious locations on the clip track 30′, including inside the opposedside rails or along the entire length of the clip track 30′, or atvarious locations on the feeder shoe 34 _(x), in the illustratedembodiment two protrusions 82 d ₁, 82 d ₂ are formed adjacent to theproximal end of the clip track 30′ and they are positioned to preventinitial migration of the feeder shoe prior to use, e.g., duringshipping. The size of the protrusions 82 d ₁, 82 d ₂ can vary dependingupon the amount of frictional force necessary to prevent unintentionalmigration of the feeder shoe 34 _(x).

While the protrusions 82 d ₁, 82 d ₂ can be configured to provide asufficient amount of friction to prevent unintentional migration of thefeeder shoe 34 _(x), the feeder shoe 34 _(x) and/or clip track 30′ canoptionally include a feature that is adapted to engage correspondingsurface protrusions. FIG. 28B illustrates opposed tangs 82 e ₁, 82 e ₂formed on a distal portion of the feeder shoe 34 _(x) for engaging theprotrusions 82 d ₁, 82 d ₂ on the clip track 30′. The tangs 82 e ₁, 82 e₂ can vary in shape and size, and they can include a lip or otherprotrusion configured to engage or “catch” the protrusions 82 d ₁, 82 d₂. As shown in FIG. 28B, the tangs 82 e ₁, 82 e ₂ extend toward oneanother from opposed sidewalls of the feeder show 34 _(x).

FIGS. 29A-29C illustrate another embodiment of a technique forpreventing unintentional migration of the feeder shoe. In thisembodiment, friction is generated between the feeder shoe and the feedbar. In particular, the feeder shoe 34 _(y) includes a tang 82 _(f) witha lip 82 _(g) formed thereon, as shown in FIG. 29A, and the feed bar 38_(y) includes a corresponding groove 84 _(y) formed therein. In use, asshown in FIG. 29C, the lip 82 _(g) is configured to engage the groove 84_(y) to prevent unintentional migration of the feeder shoe 34 _(y). Thelip 82 _(g) and groove 84 _(y), however, are configured to allowmovement of the feeder shoe 34 y when a sufficient force is applied tothe feeder shoe 34 _(y) by actuation of the trigger 16.

A person skilled in the art will appreciate that a variety of othertechniques can be used to prevent unintentional migration of a feedershoe or other clip advancement mechanism within a clip track, and thatany combination of features can be used and positioned at variouslocations on one or both components.

FIGS. 7-9 illustrate various exemplary components of a clip formingassembly. Referring first to FIG. 7, an exemplary embodiment of the jaws20 are shown. As previously mentioned, the jaws 20 can include aproximal portion 20 a having teeth 94 for mating with correspondingteeth 78 formed on the jaw retaining shaft 28. Other techniques can,however, be used to mate the jaws 20 to the jaw retaining shaft 28. Forexample, a dovetail connection, a male-female connection, etc., can beused. Alternatively, the jaws 20 can be integrally formed with theretaining shaft 28. The distal portion 20 b of the jaws 20 can beadapted to receive a clip therebetween, and thus the distal portion 20 bcan include first and second opposed jaw members 96 a, 96 b that aremovable relative to one another. In an exemplary embodiment, the jawmembers 96 a, 96 b are biased to an open position, and a force isrequired to move the jaw members 96 a, 96 b toward one another. The jawmembers 96 a, 96 b can each include a groove (only one groove 97 isshown) formed therein on opposed inner surfaces thereof for receivingthe legs of a clip in alignment with the jaw members 96 a, 96 b. Thejaws members 96 a, 96 b can also each include a cam track 98 a, 98 bformed therein for allowing the cam 42 to engage the jaw members 96 a,96 b and move the jaw members 96 a, 96 b toward one another. In anexemplary embodiment, the cam track 98 a, 98 b is formed on a superiorsurface of the jaw members 96 a, 96 b.

FIG. 8 illustrates an exemplary cam 42 for slidably mating to andengaging the jaw members 96, 96 b. The cam 42 can have a variety ofconfigurations, but in the illustrated embodiment it includes a proximalend 42 a that is adapted to mate to a push rod 44, discussed in moredetail below, and a distal end 42 b that is adapted to engage the jawmembers 96 a, 96 b. A variety of techniques can be used to mate the cam42 to the push rod 44, but in the illustrated exemplary embodiment thecam 42 includes a female or keyed cut-out 100 formed therein and adaptedto receive a male or key member 102 formed on the distal end 44 b of thepush rod 44. The male member 102 is shown in more detail in FIG. 9,which illustrates the push rod 44. As shown, the male member 102 has ashape that corresponds to the shape of the cut-out 100 to allow the twomembers 42, 44 to mate. A person skilled in the art will appreciate thatthe cam 42 and the push rod 44 can optionally be integrally formed withone another. The proximal end 44 a of the push rod 44 can be adapted tomate to a closure link assembly, discussed in more detail below, formoving the push rod 44 and the cam 42 relative to the jaws 20.

As is further shown in FIG. 8, the cam 42 can also include a protrusion42 c formed thereon that is adapted to be slidably received within anelongate slot 20 c formed in the jaws 20. In use, the protrusion 42 cand the slot 20 c can function to form a proximal stop for the clipforming assembly.

Referring back to FIG. 8, the distal end 42 b of the cam 42 can beadapted to engage the jaw members 96 a, 96 b. While a variety oftechniques can be used, in the illustrated exemplary embodiment thedistal end 42 b includes a camming channel or tapering recess 104 formedtherein for slidably receiving the cam tracks 98 a, 98 b on the jawmembers 96 a, 96 b. In use, as shown in FIGS. 10A and 10B, the cam 42can be advanced from a proximal position, in which the jaw members 96 a,96 b are spaced a distance apart from one another, to a distal position,in which the jaw members 96 a, 96 b are positioned adjacent to oneanother and in a closed position. As the cam 42 is advanced over the jawmembers 96 a, 96 b, the tapering recess 104 will push the jaw members 96a, 96 b toward one another, thereby crimping a clip disposedtherebetween.

As previously mentioned, the surgical clip applier 10 can also include atissue stop 46 for facilitating positioning of the tissue at thesurgical site within jaws 20. FIG. 11A shows one exemplary embodiment ofa tissue stop 46 having proximal end and distal ends 46 a, 46 b. Theproximal end 46 a can be adapted to mate to a distal end of the cliptrack 30 for positioning the tissue stop 46 adjacent to the jaws 20.However, the tissue stop 46 can be integrally formed with the clip track30, or it can be adapted to mate to or be integrally formed with avariety of other components of the shaft 18. The distal end 46 b of thetissue stop 46 can have a shape that is adapted to seat a vessel, duct,shunt, etc. therebetween to position and aligned the jaws 20 relative tothe target site. As shown in FIG. 11A the distal end 46 b of the tissuestop 46 is substantially v-shaped. The distal end 46 b can also have acurved configuration to facilitate placement of the device through atrocar or other access tube.

The tissue stop, or other components of the device, can also optionallyinclude features to support and stabilize a clip during clip formation.When a clip is being formed between the jaws, the clip can pivot andbecome misaligned. In particular, as the jaws are closed, the terminalend of each leg of the clip will be moved toward one another. As aresult, the jaws will only engage a bend portion on each leg, thusallowing the terminal ends of the legs and the apex of the clip to swingout of alignment with the jaws, i.e., to pivot vertically relative tothe jaws. Further closure of the jaws can thus result in a malformedclip. Accordingly, the device can include features to align and guidethe clip into the jaws, and to prevent the clip from pivoting orotherwise becoming misaligned during clip formation.

While the alignment feature can have a variety of configurations, and itcan be formed on various components of the device, FIG. 11A illustratesa central tang 47 formed at a mid-portion of the distal end 46 b of thetissue stop 46 for maintaining a clip in alignment with the tip of theadvancer assembly 40. In particular, the central tang 47 can allow theapex of a clip to ride therealong thus preventing the clip from becomingmisaligned relative to the advancer assembly 40 that is pushing the clipin a distal direction. A person skilled in the art will appreciate thatthe tissue stop 46 can have a variety of other configurations, and itcan include a variety of other features to facilitate advancement of aclip therealong.

FIG. 12A illustrates the tissue stop 46 in use. As shown, the tissuestop 46 is positioned just inferior to the jaws 20 and at a locationthat allows a vessel, duct, shunt etc. to be received between the jaws20. As is further shown, a surgical clip 36 is positioned between thejaws 20 such that the bight portion 36 a of the clip 36 is aligned withthe tissue stop 46. This will allow the legs 36 b of the clip 36 to befully positioned around the vessel, duct, shunt, or other target site.

FIGS. 11B-11D illustrate another exemplary embodiment of a tissue stop46′ having an alignment feature or guide member formed thereon andadapted to align and guide the clip into the jaws, and more preferablyto maintain the clip in alignment with the jaws during clip formation.In this embodiment, the alignment feature is in the form of a rampedmember 47′ extending longitudinally along a central axis of the tissuestop 46′ and protruding above a superior surface of the tissue stop 46′.The ramped member 47′ is preferably rigid, and increases in height froma proximal end 46 a′ to a distal end 46 b′ of the tissue stop 46′. Theangle can vary, however, depending on the particular angle of the jaws.The ramp member 47′ preferably terminates just proximal to thetissue-receiving recess 46 c′ formed in the distal tip of the tissuestop 46′. As a result, the ramped member 47′ is positioned just proximalto the jaws 20, thus allowing the ramped member 47′ to guide a clip, aswell as the tip of the advancer assembly 40 that is pushing the clip,into the jaws 20 at an appropriate angle. In use, the ramped member 47′can abut against an inferior surface of the apex of a clip disposedbetween the jaws 20 to prevent the clip from pivoting vertically as thejaws 20 are closed to form the clip. In particular, when the advancerassembly 40 is moved to the distal-most position along the ramped member47′, the apex of the clip will abut against the surface of the rampedmember 47′. As the clip is compressed between the jaws 20 and the legsof the clip move toward one another, the jaws 20 will only engage a bendportion on each leg. As a result, legs and the apex of the clip are freeto pivot vertically. However, since the apex is resting against thesuperior surface 47 a′ of the ramped member 47′, the ramped member 47′will prevent the apex from moving vertically in a downward or inferiordirection, thereby preventing the legs of the clip from movingvertically in an upward or superior direction, i.e., the ramped member47′ will prevent the clip from swinging within the jaws 20. Thus, theramped member 47′ is effective to prevent or limit harmful rotationalforces generated when the jaws 20 are closed to form the clip. The clipis thus maintained in alignment with the jaws 20.

A person skilled in the art will appreciate that the shape, size, andconfiguration of the ramp member can vary depending on the particularconfiguration of the jaws and other components of the clip applier. Inone exemplary embodiment, the ramped member 47′ can have a maximumheight h_(Rmax) of about 0.025″, as measured from a central planeextending through the tissue stop 46′. More preferably the heighth_(Rmax) is in the range of about 0.008″″ to 0.020″, and most preferablythe height h_(Rmax) is in the range of about 0.010″ to 0.015″. Theincline angle α_(R) of the ramped member 47′ can also vary, but in anexemplary embodiment the ramped member 47′ has an incline angle α_(R) inthe range of about 5° to 45°, and more preferably 5° to 30°, and mostpreferably 10° to 20°. The width w_(r) of the ramped member 47′ can alsovary, but in an exemplary embodiment the ramped member 47′ preferablyhas a width w_(r) that is slightly less than a space between the jaws 20in the fully closed position.

FIGS. 11E and 11F illustrate another exemplary embodiment of a tissuestop 46″ having proximal and distal ends 46 a″, 46 b″. The proximal end46 a″ can be adapted to mate to a distal end of the clip track 30 forpositioning the tissue stop 46″ adjacent to the jaws 20. However, inother embodiments the tissue stop 46″ can be integrally formed with theclip track 30, or it can be adapted to mate to or be integrally formedwith a variety of other components of the shaft 18. The distal end 46 b″of the tissue stop 46″ can have a shape that is adapted to seat avessel, duct, shunt, etc. therebetween to position and align the jaws 20relative to the target site. For example the tissue stop 46″ can have aV-shape that is defined, at least in part, by first and second arms 39a, 39 b.

In this embodiment, the tissue stop 46″, also referred to as a guidemember or advancer guide, is particularly configured for use with theadvancer 40″ shown in FIGS. 5C and 5D. In particular, the tissue stop46″ includes features to accommodate the increased height of theadvancer tip 90″ as previously discussed. As shown in FIGS. 11E and 11F,the tissue stop 46″ can include an opening or channel 49 formed thereinand adapted to allow the distal tip 90″ of the advancer 40″ to deflectin an inferior direction, i.e., into or through the channel 49, duringmovement of the advancer 40″ between proximal and distal positions.While the channel 49 can be located at any position on the tissue stop46″, in the embodiment the channel 49 is disposed at a central toproximal location longitudinally along the tissue stop 46″. The channel49 can also be located in a recessed track 46 t formed in a superiorsurface 46 s of the tissue stop 46″, such that the channel 49 is locateda distance apart and inferior to the superior surface 46 s. The recessedtrack 46 t can be in the form on a longitudinally extending cut-outformed along a substantial portion of the tissue stop 46″, so as tocreate opposed side rails 46 r extending longitudinally along asubstantial length of the tissue stop 46″. The guide rails 46 r allowthe advancer 40″ to slide there along at a location above the channel49.

As further shown in FIGS. 11E and 11F, the recessed track 46 t caninclude a sloped or ramped surface adjacent to proximal and distal endsof the channel 49, such that the channel 49 includes a distal ramp 51and a proximal ramp 53. The distal ramp 51 can increase in height in theinferior to superior direction from a proximal end to a distal end. Thedistal ramp 51 can function to deflect the advancer tip 90″ in asuperior direction as the advancer 40″ is advanced distally. Theproximal ramp 53 can increase in height in the inferior to superiordirection from a distal end to a proximal end. The proximal ramp 53 canfunction to deflect the advancer tip 90″ in a superior direction as theadvancer 40″ is advanced proximally.

As further shown in FIGS. 11E and 11F, the tissue stop 46″ can alsoinclude a longitudinally-extending groove 55 located distal to thechannel 49 and adjacent to the distal end. The groove 55 can extendalong the longitudinal axis of the tissue stop 46″ in a substantiallycentral location laterally between the first and second arms 39 a, 39 band it can be positioned substantially directly in line with the channel49 such that the distal tip 90″ traveling distally up the distal ramp 51and out of the channel 49 can continue traveling in a straight linealong the groove 55 to move a clip over the tissue stop 46″. In otherwords, the groove 55 substantially prevents the distal tip 90″ frommoving laterally relative to opposed lateral sides of the tissue stop46″ to keep the tip 90″ in alignment with the apex of the clip. In someembodiments, the groove 55 can be recessed below a top surface of thefirst and second arms 39 a, 39 b to accommodate the increased height Hof the distal tip 90″. Since an apex of a clip generally travels adistance above the tissue stop 46″, this allows a height H of a distaltip 90″ to extend both above and below the apex of the clip.

As noted above, when the clip is pushed into the jaws 20, the clip mustreorient itself to accommodate the angle of the jaws 20. Thisreorientation can cause an apex of the clip to drop vertically or rotatedownward (in an inferior direction) relative to the opposed legs of theclip. This drop may prevent the clip from being positioned properlywithin the jaws 20. For example, in some cases, the apex of the clip maydrop below a distal end of the clip-pusher member such that theclip-pusher member bypasses the clip and moves over top of its apex. Theclip-pusher member would then be unable to properly position the clipwithin the jaws 20. The height H of the clip-pusher member 90″ in theembodiment shown in FIGS. 5C and 5D, however, in combination with thegroove 55 in the tissue stop 46″ in the embodiment shown in FIGS. 11Eand 11F, provides a solid surface against which the apex of the clip canmove if it pivots in the superior and/or inferior directions. If theapex of the clip drops as it is being pushed into the jaws 20, thedistal facing surface 41 of the distal tip 90″ can provide a solidsurface that extends down into the recessed groove 55, therebypreventing the apex of the clip from slipping beneath the distal tip90″. In this way, an apex of a clip cannot fall below an inferiorsurface of the distal facing surface 41, thereby allowing the clip toalways maintain contact with the distal tip 90″ and thus to always bepositioned properly within the jaws 20.

FIGS. 12B-12E illustrate an exemplary interaction between the tissuestop 46″ and the distal tip 90″ in more detail. In FIG. 12B, the distaltip 90″ is near the beginning of a clip forming cycle. The distal tip90″ is shown pushing the distal-most clip C into the jaws 20. The nextclip C₁ can be at a distal position in the clip track 30. As shown, thedistal-facing surface 41 of the distal tip 90″ is abutting an apex ofthe clip C and it has a height H that is substantially greater than aheight of the apex. The distal-facing surface 41 of the distal tip 90″can travel within the groove 55 of the tissue stop 46″ as it pushes theclip C into the jaws 20. In this way, as the legs of the clip C rotateupward (in a superior direction) slightly to enter the jaws 20, the apexof the clip C will always abut against the distal-facing surface 41,even if the apex pivots downward in the inferior direction. Moreparticularly, the inferior surface of the distal tip 90″ is in contactwith the groove 55, and thus the apex of the clip C will never fallbelow the inferior surface of the distal tip 90″. In this way, thedistal-facing surface 41 is able to maintain contact with the apex ofthe clip C at all times and is therefore able to position the clip Cproperly within the jaws 20. The distal-facing surface 41 can alsomaintain contact with the apex of the clip C at all times during formingof the clip C between the jaws 20 to ensure that the clip C does notmove proximally.

As illustrated in FIG. 12C, once the clip C is formed within the jaws 20and released, the distal tip 90″ begins moving proximally from itsdistal-most position within the groove 55 in order to position itselfbehind or proximal to the next clip C₁. At this point in the clipforming cycle, the distal tip 90″ is positioned distal to the next clipC₁, and the highest point on the superior surface 47 of the distal tip90″ is at substantially the same height as the superior surface of theclip C₁. Therefore, as the distal tip 90″ moves proximally into contactwith the clip C₁, the superior surface 47 of the distal tip 90″ cancontact an inferior surface of an apex of the clip C₁. Since the clip C₁is rigidly held within the clip track 30, the clip C₁ produces adownward force on the distal tip 90″ to deflect the resilient distal tip90″ downward. As the clip C₁ and the superior surface 47 of the distaltip 90″ contact one another, the distal tip 90″ is traveling toward thedistal ramp 51. Thus, the downward force applied by the clip C₁ cancause the distal tip 90″ to deflect downward in an inferior directionsuch that the distal biasing surface 43 of the distal tip 90″ travelsdown the distal ramp 51 and into or partially through the channel 49.With the distal tip 90″ traveling proximally in the channel 49, itssuperior surface 47 is lower than an inferior surface of the apex of theclip C₁ and can thus travel proximally under the inferior surface of theapex of the clip C₁, as shown most clearly in FIG. 12D.

As the distal tip 90″ continues to move proximally within the channel49, the distal-facing surface 41 moves proximal to the apex of the clipC₁. As it moves proximally, the proximal biasing surface 45 contacts theproximal ramp 53 and begins to move up the proximal ramp 53. Since thesuperior surface 47 of the distal tip 90″ is no longer in contact withthe inferior surface of the clip C₁, when the proximal biasing surface45 travels up the proximal ramp 53, the distal tip 90″ deflects back upin a superior direction such that it is of a substantially even heightwith the apex of the clip C₁ once again, as shown most clearly in FIG.12E. The distal tip 90″ is now in its proximal-most position and isready to begin the clip forming cycle over again. Thus, as the advancer40″, and hence the distal tip 90″, are moved distally, the distalbiasing surface 43 on the distal tip 90″ will travel distally along thedistal ramp 51 to cause the distal tip 90″ to deflect upward in thesuperior direction, thus ensuring that contact is maintained between theapex of the clip and the distal-facing surface 41 of the distal tip 90″.

FIGS. 13-26B illustrate various exemplary internal components of thehousing 12 for controlling clip advancement and forming. As previouslydiscussed, the surgical clip applier 10 can include some or all of thefeatures disclosed herein, and it can include a variety of otherfeatures known in the art. In certain exemplary embodiments, theinternal components of the clip applier 10 can include a clip advancingassembly, that couples to the clip advancing assembly of the shaft 18,for advancing at least one clip through the elongate shaft 18 toposition the clip between the jaws 20, and a clip forming assembly, thatcouples to the clip forming assembly of the shaft 18, for closing thejaws 20 to form a partially or fully closed clip. Other exemplaryfeatures include an anti-backup mechanism for controlling movement ofthe trigger 16, an overload mechanism for preventing overload of theforce applied to the jaws 20 by the clip forming assembly, and a clipquantity indicator for indicating a quantity of clips remaining in thedevice 10.

FIGS. 13-16D illustrate an exemplary embodiment of a clip advancingassembly of the housing 12 for effecting movement of the feed bar 38within the shaft 18. In general, the clip advancing assembly can includea trigger insert 48 that is coupled to the trigger 16, a feed barcoupler 50 that can mate to a proximal end 38 a of the feed bar 38, anda feed link 52 that is adapted to extend between the trigger insert 48and the feed bar coupler 50 for transferring motion from the triggerinsert 48 to the feed bar coupler 50.

FIG. 14 illustrates the trigger insert 48 in more detail. The shape ofthe trigger insert 48 can vary depending on the other components of thehousing 12, but in the illustrated embodiment the trigger insert 48includes a central portion 48 a that is adapted to pivotally mate to thehousing 12, and an elongate portion 48 b that is adapted to extend intoand mate to the trigger 16. The central portion 48 a can include a bore106 extending therethrough for receiving a shaft for pivotally matingthe trigger insert 48 to the housing 12. The central portion 48 a canalso include a first recess 108 formed in a superior side edge forreceiving a portion of the feed link 52. The first recess 108 preferablyhas a size and shape that allows a portion of the feed link 52 to extendtherein such that the feed link 52 will be forced to pivot when thetrigger insert 48 pivots due to movement of the trigger 16. As shown inFIG. 14, the first recess 108 is substantially elongate and includes asubstantially circular portion formed therein for seating a shaft formedon a proximal end of the feed link 52, as will be discussed in moredetail with respect to FIG. 16. The trigger insert 48 can also include asecond recess 110 formed in a back side edge for receiving a closurelink roller 54 that is coupled to the push bar 44 for moving the cam 42to close the jaws 20, and ratchet teeth 112 formed on the bottom sideedge thereof for mating with a pawl 60 for controlling movement of thetrigger 16, as will be discussed in more detail below.

The exemplary feed bar coupler 50 is shown in more detail in FIGS. 15Aand 15B, and it can be adapted to couple the proximal end of the feedbar 38 to the distal end of the feed link 52. While a variety oftechniques can be used to mate the feed bar coupler 50 to the proximalend 38 a of the feed bar 38, in an exemplary embodiment the feed barcoupler 50 is formed from two separate halves 50 a, 50 b that matetogether to maintain the proximal end 38 a of the feed bar 38therebetween. When mated, the two halves 50 a, 50 b together define acentral shaft 50 c having substantially circular flanges 50 d, 50 eformed on opposed ends thereof and defining a recess 50 f therebetweenfor seating a distal portion of the feed link 52. The central shaft 50 cdefines a lumen 50 g therethrough for receiving the proximal end 38 a ofthe feed bar 38 and for locking the feed bar 38 in a substantially fixedposition relative to the feed bar coupler 50. The feed bar coupler 50can, however, be integrally formed with the feed bar 38, and it can havea variety of other shapes and sizes to facilitate mating with the feedlink 52.

FIG. 16 illustrates an exemplary feed link 52, which can extend betweenthe trigger insert 48 and the feed bar coupler 52. In general, the feedlink 52 can have a substantially planar elongate shape with proximal anddistal ends 52 a, 52 b. The proximal end 52 a is adapted to rotatablysit within the first recess 108 of the trigger insert 48 and thus, aspreviously discussed, it can include a shaft 53 (FIG. 1B) extendingtherethrough. The shaft 53 can be adapted to pivotally rotate within thefirst recess 108 of the trigger insert 48, thereby allowing the triggerinsert 48 to pivot the feed link 52. The distal end 52 b of the feedlink 52 can be adapted to couple to feed bar coupler 50 and thus, in anexemplary embodiment, it includes opposed arms 114 a, 114 b formedthereon and defining an opening 116 therebetween for seating the centralshaft 50 a of the feed bar coupler 50. The arms 114 a, 114 b areeffective to engage and move the coupler 50 as the feed link 52 pivotsabout a pivot axis X. The pivot axis X can be defined by the location atwhich the feed link 52 couples to the housing 12, and it can bepositioned anywhere on the feed link 52, but in the illustratedembodiment it is positioned adjacent to the proximal end 52 a of thefeed link 52.

In an exemplary embodiment, the feed link 52 can be flexible toeliminate the need to calibrate the clip advancing assembly and the clipforming assembly. In particular, the feed link 52 allows the trigger 16to continue moving toward a closed position even after the feed bar 38and feed bar coupler 50 are in a distal-most position, and it providessome freedom to the clip forming and clip advancing assemblies. In otherwords, the trigger 16 is pliant relative to the feed bar 38 duringclosure of the trigger.

The particular stiffness and strength of the feed link 52 can varydepending on the configuration of the clip advancing assembly and theclip forming assembly, but in one exemplary embodiment the feed link 52has a stiffness that is in the range of 75 to 110 lbs per inch, and morepreferably that is about 93 lbs per inch (as measured at the interfacebetween the link 52 and the feed bar coupler 50), and it has a strengthof that is in the range of 25 lbs and 50 lbs, and more preferably thatis about 35 lbs. The feed link 52 can also be formed from a variety ofmaterials, including a variety of polymers, metals, etc. One exemplarymaterial is a glass-reinforced polyetherimide, but a number ofreinforced thermoplastics could be used, including glass reinforcedliquid-crystal polymers, glass-reinforced nylons, and carbon-fiberreinforced versions of these and similar thermoplastics.Fiber-reinforced thermoset polymers such as thermoset polyesters couldalso be used. Feed link 52 could also be fabricated from a metal, suchas spring steel to achieve the desired combination of limitedflexibility and controlled strength.

FIGS. 17A-17D illustrate the exemplary clip advancing assembly in use.FIG. 17A shows an initial position, wherein the trigger 16 is resting inan open position, the feed bar coupler 50 and feed bar 38 are in aproximal-most position, and the feed link 52 extends between the triggerinsert 48 and the feed bar coupler 50. As previously discussed, in theinitial open position the protrusion 86 on the feed bar 38 in positionedin the proximal end of the elongate slot 88 in the jaw retainer shaft28. A first biasing member, e.g., spring 120, is coupled to the triggerinsert 48 and the housing 12 to maintain the trigger insert 48 andtrigger 16 in the open position, and a second biasing member, e.g.,spring 122, extends between a shaft coupler 124, which rotatably matesthe shaft 18 to the housing 12, and the feed bar coupler 50 to maintainthe feed bar coupler 50 and feed bar 38 in the proximal-most position.

When the trigger 16 is actuated and moved toward the closed position,i.e., toward the stationary handle 14, to overcome the biasing forcesapplied by the springs 120, 122, the trigger insert 48 begins to pivotin a counter-clockwise direction, as shown in FIG. 17B. As a result, thefeed link 52 is forced to pivot in a counter-clockwise direction,thereby moving the feed bar coupler 50 and feed bar 38 in a distaldirection. The protrusion 86 on the feed bar 38 thus moves distallywithin the elongate slot 88 in the jaw retainer shaft 28, therebyadvancing the feeder shoe 34 and the clips 36 disposed within the cliptrack. Spring 120 is extended between the housing and the trigger insert48, and spring 122 is compressed between the feed bar coupler 50 and theshaft coupler 124.

As the trigger 16 is further actuated and the trigger insert 48continues to pivot, the feed bar coupler 50 and feed bar 38 willeventually reach a distal-most position. In this position, theprotrusion 86 on the feed bar 38 will be positioned at the distal end ofthe slot 88 in the jaw retainer shaft 28 and a clip will be positionedbetween the jaws 20, as previously discussed. Spring 122 will be fullycompressed between the shaft coupler 124 and the feed bar coupler 50,and the feed link 52 will flex, as shown in FIGS. 17C and 17D. As thefeed link 52 flexes, and more preferably once the feed link 52 fullyflexed, the clip forming assembly will be actuated to close the jaws 20.The feed link 52 will remain flexed during actuation of the clip formingassembly, e.g., the second stage of actuation, such that the triggerinsert 48 is pliant relative to the clip advancing assembly, and inparticular the feed bar 38.

An exemplary clip forming assembly of the housing 12 is shown in moredetail in FIGS. 18-20. In general, the clip forming assembly is disposedwithin the housing 12 and it is effective to move the push rod 44 andcam 42 relative to the jaws 20 to move the jaws 20 to a closed positionand thereby crimp a clip positioned therebetween. While the clip formingassembly can have a variety of configurations, the illustrated exemplaryclip forming assembly includes a closure link roller 54 that is slidablycoupled to the trigger insert 48, a closure link 56 that is adapted tocouple to the closure link roller 54, and a closure coupler 58 that isadapted to couple to the closure link 56 and to the push rod 44.

FIG. 18 illustrates the closure link roller 54 in more detail and, asshown, the closure link roller 54 includes a central shaft 54 a havingsubstantially circular flanges 54 b, 54 c formed adjacent to the opposedterminal ends thereof. The central shaft 54 a can be adapted to sitwithin the second recess 110 in the trigger insert 48 such that theflanges 54 b, 54 c are received on opposed sides of the trigger insert48. The central shaft 54 a can also be adapted to mate to opposed arms126 a, 126 b of the closure link 56 to position the arms on opposedsides of the trigger insert 48.

An exemplary embodiment of a closure link 56 is shown in more detail inFIG. 19, and as shown it has opposed arms 126 a, 126 b that are spaced adistance apart from one another. Each arm 126 a, 126 b includes aproximal end 128 a, 128 b that is adapted to engage the central shaft 54a of the closure link roller 54, and a distal end 130 a, 130 b that isadapted to mate to a closure coupler 58 for coupling the closure linkroller 54 and closure link 56 to the push rod 44. In an exemplaryembodiment, the proximal end 128 a, 128 b of each arm 126 a, 126 b isadapted to pivotally mate to the closure link roller 54, and thus thearms 126 a, 126 b can include, for example, hook-shaped members 132 a,132 b formed thereon for engaging the central shaft 54 a. Thehook-shaped members 132 a, 132 b extend in opposite directions tofacilitate engagement between the closure link 56 and the closure linkroller 54. The distal end 130 a, 130 b of the arms 126 a, 126 b can bemated to one another, and they can include a lumen 134 extendingtherethrough for receiving a shaft that is adapted to pivotally mate theclosure link 56 to the closure coupler 58. A person skilled in the artwill appreciate that a variety of other techniques can be used to matethe closure link 56 to the closure link roller 54 and the closurecoupler 58.

An exemplary closure coupler 58 is shown in more detail in FIG. 20A, andas shown it includes a proximal portion 58 a having two arms 136 a, 136b with lumens 138 a, 138 b extending therethrough and adapted to bealigned with the lumen 134 in the closure link 56 for receiving a shaftto mate the two components. The closure coupler 58 can also include adistal portion 58 b that is adapted to mate to the proximal end 44 a ofthe push rod 44 (FIG. 9). In an exemplary embodiment, the closurecoupler 58 includes a cut-out 59 (FIGS. 20B and 20C) formed therein andhaving a shape that is adapted to seat the proximal end 44 a of the pushrod 44. The distal portion 58 b of the closure coupler 58 can also beconfigured to receive a portion of the feed bar coupler 50 when thetrigger 16 is in the open position. A person skilled in the art willappreciate that a variety of other mating techniques can be used to matethe closure coupler 58 to the push rod 44, and that the closure coupler58 and the push rod 44 can optionally be integrally formed with oneanother. The closure coupler 58 can further include side wings 71 a, 71b. The wing 71 a can be in contact with a compression spring 81,described in more detail below, to bias the closure coupler 58proximally as the trigger 16 is squeezed.

In other exemplary embodiments, a preloaded joint can be formed betweenthe push rod 44 and the closure coupler 58 to prevent accidental releaseof a clip from the jaws, particularly during the early stages ofclosure, if the user eases-up on the trigger 16. In particular, whilethe anti-backup mechanism, discussed in more detail below, can beadapted to prevent the trigger 16 from opening until the trigger 16reaches a predetermined position, the anti-backup mechanism may allowsome minor movement of the trigger 16. Thus, in the event a usereases-up on the trigger 16 and minor opening of the trigger 16 occurs,the preloaded joint will bias the push rod 44 in a distal direction,thereby maintaining the push rod 44 in a substantially fixed position,while allowing the closure coupler 58 to move proximally until thetrigger 16 is engaged by the anti-backup mechanism.

While the preloaded joint can have a variety of configurations, and itcan be positioned at various locations along the clip forming assembly,in one exemplary embodiment the preloaded joint can be in the form of abiasing member disposed within the cut-out 59 to bias the push rod 44 ina distal direction. While a variety of biasing members can be used, inthe embodiment shown in FIG. 20B, the biasing member is a cantileveredbeam 61 that is positioned between the proximal end 44 a of the push rod44 and the back wall of the recess 59 to bias the push rod 44 distally.The cantilevered beam 61 can be formed from a shape memory material,such as Nitinol, that allows the beam 61 to flex or flatten when aproximally-directed force is applied thereto. The beam 61 can also beformed from a variety of other materials, such as spring steel orreinforced polymers, and more than one beam can be used. FIG. 20Cillustrates another embodiment of a biasing member which is in the formof a coil or other type of spring 63. As shown, the spring 63 isdisposed between the proximal end 44 a of the push rod 44 and the backwall of the recess 59 to bias the push rod 44 distally. The spring 63 isadapted to compress when a proximally-directed force is applied thereto.A person skilled in the art will appreciate that a variety of otherbiasing members can be used, including elastomeric compression members.

The preloaded joint can also optionally include features to enhanceperformance of the cantilevered beam or spring during the clip formingprocess. In the embodiment shown in FIG. 20B, the load of thecantilevered beam 61 remains primarily uniform as the cantilevered beamis compressed during closure, however the load increases significantlyduring the final stages of closure. This is illustrated in FIG. 20D,which shows a graph of the load/displacement curve of the cantileveredbeam 61 shown in FIG. 20B. The left end of the curve represents theunloaded height of the cantilevered beam 61, while the right end of thecurve represents the point at which the cantilevered beam 61 is fullycompressed or flattened. The upper curve represents the force resultingas the cantilevered beam 61 is compressed during a typical closingstroke, with the exception that the force is measured from a free stateof the cantilevered beam 61 whereas the cantilevered beam 61 isinitially partially compressed when it is disposed within the closurecoupler 58. As shown, the load remains substantially constant (excludingthe initial compression stages), increasing only slightly during theclosing stroke as the cantilevered beam 61 is being compressed. However,the load increases significantly at the final stages of closure when thecantilevered beam 61 is fully flattened. This is due to deflection ofthe cantilevered beam 61 which causes the load to be transferred fromthe terminal ends of the cantilevered beam 61 inward. As thecantilevered beam 61 deflects and the load is transferred inward, theeffective length of the cantilevered beam 61 is decreased, therebyincreasing the load. In order to prevent this, the preloaded joint canoptionally include features to enhance the cantilevered beam or springperformance, and in particular to maintain a substantially constant loadduring clip formation.

FIG. 20E illustrates one exemplary embodiment of a technique forenhancing the cantilevered beam or spring performance. As shown, therecess 59′ in the closure coupler 58′ includes two ridges 59 a′, 59 b′formed therein on the back surface thereof such that the ridges 59 a′,59 b′ are positioned underneath or behind the cantilevered beam (notshown). The ridges 59 a′, 59 b′ are spaced a distance apart from oneanother and each ridge 59 a′, 59 b′ has a height of at least about0.005″ to prevent the cantilevered beam from fully flattening againstthe back surface of the recess. As a result, the ridges 59 a′, 59 b′will prevent the cantilevered beam from deflecting, thereby preventingthe load of the spring or cantilevered beam from transferring from theterminal ends inward. A person skilled in the art will appreciate thatthe particular location, quantity, and size of the ridges 59 a′, 59 b′can vary depending on the configuration of the preloaded joint, as wellas the forces necessary to prevent clip fallout during closure.

In use, referring back to FIGS. 17A-17D, as the trigger 16 is initiallymoved from the open position toward the closed position, the closurelink roller 54 will roll within the recess 110 in the trigger insert 48.Once the feed bar 38 and feed bar coupler 50 are in the distal-mostposition, as shown in FIG. 17C, further actuation of the trigger 16 willcause the recess 110 in the trigger insert 48 to engage the closure linkroller 54 forcing it to pivot with the trigger insert 48, as shown inFIG. 17D. As a result, the closure coupler 58 will move distally,thereby causing the push rod 44 to move distally. As the push rod 44advances distally, the cam 42 is advanced over the jaws 20 to close thejaws 20 and crimp the clip positioned therebetween. The trigger 16 canoptionally be partially closed to only partially close the jaws 20 andthus partially crimp a clip disposed therebetween. Exemplary techniquesfor facilitating selective full and partial closure of the clip will bediscussed in more detail below. Once the clip is applied, the trigger 16can be released thereby allowing spring 120 to pull the trigger insert48 back to its initial position, and allowing spring 122 to force thefeed bar coupler 50 and feed bar 38 back to the proximal position. Asthe trigger insert 48 returns to its initial position, the closure linkroller 54 is moved back to its initial position as well, thereby pullingthe closure link 56, closure coupler 58, and push bar 44 proximally.

The surgical clip applier 10 can also include a variety of otherfeatures to facilitate use of the device 10. In one exemplaryembodiment, the surgical clip applier 10 can include an anti-backupmechanism for controlling movement of the trigger 16. In particular, theanti-backup mechanism can prevent the trigger 16 from opening during apartial closing stroke. However, once the trigger reaches apredetermined position, at which point the clip positioned between thejaws can be partially crimped, the anti-backup mechanism can release thetrigger allowing the trigger to open and release the clip or to close tofully crimp the clip, as may be desired by the user.

FIGS. 21A and 21B illustrate one exemplary embodiment of an anti-backupmechanism in the form of a ratchet. As shown, the ratchet includes a setof teeth 112 formed on the trigger insert 48, and a pawl 60 that isadapted to be rotatably disposed within the housing 12 and positionedadjacent to the trigger insert 48 such that closure of the trigger 16and pivotal movement of the trigger insert 48 will cause the pawl 60 toengage the teeth 112. The teeth 112 can be configured to preventrotation of the pawl 60 until the pawl 60 reaches a predeterminedposition, at which point the pawl 60 is free to rotate, thereby allowingthe trigger 16 to open or close. The predetermined position preferablycorresponds to a position at which the jaws 20 are partially closed. Inan exemplary embodiment, as shown, the teeth 112 include a first set ofteeth 112 a, e.g., ten teeth, having a size that prevents rotation ofthe pawl 60 relative thereto, thus preventing the trigger 16 fromopening when the pawl 60 is engaged with the first set 112 a of teeth112. The teeth 112 can also include a final or terminal tooth, referredto as a tock tooth 112 b, that has a size that allows the pawl 60 torotate relative thereto when the pawl 60 is engaged with the tock tooth112 b. In particular, the tock tooth 112 b preferably has a size that issubstantially greater than the size of the first set of teeth 112 a suchthat a relatively large notch 140 is formed between the first set ofteeth 112 a and the tock tooth 112 b. The notch 140 has a size thatallows the pawl 60 to pivot therein, thus allowing the pawl 60 to beselectively moved beyond the tock tooth 112 b or back toward the firstset of teeth 112 a. A person skilled in the art will appreciate that thetock tooth 112 b can have the same size or a smaller size than the firstten teeth 112 a while still providing a notch 140 formed therebetweenthat allows the pawl 60 to pivot therein.

FIGS. 22A-22D illustrates the ratchet mechanism in use. When the trigger16 is initially moved toward a closed position, as shown in FIG. 22A,the pawl 60 will engage the first set of teeth 112 a thereby preventingthe trigger 16 from opening. Further actuation of the trigger 16 willcause the pawl 60 to advance past the first set of teeth 112 a until thepawl 60 reaches the notch 140 next to the tock tooth 112 b. Once thepawl 60 reaches the tock tooth 112 b, at which point the jaws 20 arepartially closed due the partial distal movement of the cam 42 over thejaws 20, the pawl 60 is free to rotate thereby allowing the trigger 16to open or close, as may be desired by the user. FIG. 22C illustratesthe trigger 16 in a fully closed position, and FIGS. 22D and 22Eillustrate the trigger 16 returning to the open position.

As previously explained herein, in other embodiments the clip appliercan include a stop mechanism for indicating to a user when the clipsupply is depleted. In an exemplary embodiment, the stop mechanism canbe operatively associated with the ratchet mechanism to aid inmaintaining the trigger in a fixed, partially opened position after thelast clip is applied. In particular, the stop mechanism can beconfigured to activate when the pawl 60 is engaged with the teeth 112 a,and prior to the pawl 60 reaching the notch during the opening stroke.In this position, the pawl 60 is unable to rotate in either direction,thus preventing the trigger 16 from moving, and thereby providingfeedback to a user through the trigger 16 that the clip supply isdepleted. As previously described, in one embodiment the stop mechanismcan be in the form of a tang 82 d′ formed on the feeder shoe 34″′, andrecesses 51 a, 51 b formed in the advancer 40″ and feed bar 38″. Afterthe proximal-most clip is formed, the trigger 16 can be released to movefrom the fully closed position toward the open position, thereby causingthe feed bar 38′ and the advancer 40″ to retract proximally. Proximalmovement of the feed bar 38″ will cause the pawl 60 to re-engage theteeth 122 b, 112 a. With the pawl 60 in engagement with the teeth 112 a,and before the pawl 60 reaches the notch 140, the recesses 51 a, 51 bformed in the advancer 40″ and the feed bar 38′ will engage with thetang 82 d′ on the feeder shoe 34″′ to prevent further proximal movementof the feed bar 38′ and the advancer 40′. The fixed or locked positionof the feed bar 38′ and the advancer 40″ thus prevents the pawl 60 fromreaching the notch 140. As a result, the pawl 60 cannot rotate and thusthe trigger 16 is prevented from opening or closing, and is therebylocked in a fixed, partially closed position preventing further use ofthe device.

While the trigger 16 is locked in a partially opened position after thelast clip is applied, the jaws 20 should fully open to allow the clip tobe released. This can be achieved by adding a biasing element, such as acompression spring 81 as shown in FIGS. 22F and 22G, that biases thepush rod 44 to the proximal position. The spring 81 can be disposedanywhere within the housing 12, but in the illustrated embodiment, thespring 81 is disposed between a wall 91 of the housing 12 and a wing 71a formed on the closure coupler 58. A distal end of the spring 81 canabut up against the wall 91 of the housing 12, and a proximal end of thespring 81 can abut against the wing 71 a of the closure coupler 58 tobias the closure coupler 58 in a proximal direction, which in turnbiases a proximal end 44 a of the push rod 44 in a proximal direction.Thus, when the trigger 16 is fully closed, the spring 81 is compressedbetween the wall 91 of the housing 12 and the wing 71 a, biasing theclosure coupler 58, and hence the push rod 44, proximally. The trigger16, however, prevents any proximal movement of the closure coupler 58and the push rod 44. As the trigger 16 is partially released from itsfully closed position, the spring 81 will move the closure coupler 58,and thus the push rod 44, proximally to allow the jaws 20 to open andrelease the clip. The jaws 20 will thus open before the trigger 16 isfully opened and, in particular, before the trigger 16 is locked by thelockout mechanism.

The ratchet mechanism can also be configured to emit an audible soundthat indicates the position of the jaws 20. For example, a first soundcan be emitted when the pawl 60 engages the first set of teeth 112 a,and a second, different sound, e.g., a louder sound, can be emitted whenthe pawl 60 engages the tock tooth 112 b. As a result, when the trigger16 reaches the predetermined position at which the pawl 60 is engagedwith the tock tooth 112 b, the sound indicates to the user that the jaws20 are in the partially closed position. The user can thus release thetrigger 16 to release a partially closed clip, or they can fully closethe trigger 16 to fully close the clip.

In another exemplary embodiment, the surgical clip applier 10 caninclude an overload mechanism that is adapted to prevent overload of aforce applied to the jaws 20 by the trigger 16. Typically, duringapplication of a surgical clip, a certain force is required to close thejaws 20 and crimp the clip around the tissue positioned therebetween. Asthe forming process proceeds and the clip is at least partially closed,the force required to continue closing the jaws 20 around the clipsignificantly increases. Accordingly, in an exemplary embodiment, theoverload mechanism can have a resistance that correlates to the forcerequired to close the jaws 20. In other words, the resistance of theoverload mechanism can increase as the force required to close the jaws20 increases. The resistance is, however, preferably slightly greaterthan the force required to close the jaws 20 to prevent accidentalactuation of the overload mechanism. As a result, if the jaws 20 areprevented from closing when the trigger 16 is initially actuated, theforce required to overcome the resistance of the overload mechanism isrelatively low. This is particularly advantageous as the jaws 20 aremore susceptible to being deformed when they are open or only partiallyclosed. The overload mechanism will actuate more readily in the earlystages of clip formation to prevent deformation of the jaws. Conversely,when the jaws 20 are substantially closed, the resistance is relativelyhigh such that the overload mechanism can only be actuated uponapplication of a significant force applied to the jaws 20.

FIG. 23A illustrates one exemplary embodiment of an overload mechanism62, showing an exploded view. In general, the overload mechanism caninclude an overload housing 64 formed from two halves 64 a, 64 b andcontaining a profile link 66, a toggle link 68, a pivot link 70, and abiasing assembly 72. The biasing assembly 72 can include a spring post150 that is coupled to the housing 64 and that includes a bore extendingtherethrough for receiving a plunger 154. A spring 152 is disposedaround the spring post 150, and the plunger 154 extends through thespring post 150 and includes a head 154 a formed thereon that is adaptedto abut against the spring 152. The pivot link 70 can be generallyL-shaped and it can be coupled to the housing 64 by a pivot pin 156extending therethrough. A proximal end 70 a of the pivot link 70 cancontact the head 154 a of the plunger 154, and a distal end 70 b of thepivot link 70 can be pivotally coupled to the toggle link 68 by a pivotpin 166. The toggle link 68, in turn, can be coupled to the profile link66, which can be slidably and pivotally positioned within the housing 64adjacent to an opening 64 d formed in the housing. Pivotal movement ofthe profile link 66 within the housing 64 can be achieved by, forexample, a pivot pin 158 that extends through the profile link 66 and isthat disposed within a first slot 160 a (only one slot is shown) formedin each half 64 a, 64 b of the housing 64, and slidable movement of theprofile link 66 within the housing 64 can be achieved by, for example,opposed protrusions 168 a, 168 b formed on the profile link 66 that arereceived within a second slot 160 b (only one slot is shown) formed ineach half 64 a, 64 b of the housing 64.

In use, the profile link 66 can be adapted to receive a force from theclip forming assembly and to counter the force with the resistance ofthe biasing assembly 72. In particular, the overload mechanism 62 usesthe spring 152 along with the toggle link 68 and pivot link 70 to biasthe profile link 66 from either rotating about the pivot pin 158 orsliding against the housing 64. For the rotational aspect, the forceexerted by the compressed spring 152 is transferred through the togglelink 68 and pivot link 70, such that a rotational moment is applied tothe profile link 66 against the housing 64. Thus this assembly causesthe profile link 66 to resist rotation with respect to the housing 64.If the moment generated by a radial load from the closure link roller 54against the profile link 66 exceeds the moment of the pivot link 70 andtoggle link 68, the profile link 66 begins to rotate, buckling thetoggle link 68 and causing the pivot link 70 to further compress thespring 152. For the sliding aspect, the pivot link 70, toggle link 68,and profile link 66 are aligned such that the sliding force (resistanceto slide) is the force required to buckle the toggle link 68 and pivotlink 70. If the radial load from the closure link roller 54 against theprofile link 66 exceeds the buckling force of the linkages, then thepivot link 70 further compresses the spring 152 as the profile link 66slides proximally.

This is shown in more detail in FIGS. 23B-23C, and as shown the opening64 d in the housing 64 allows the closure link roller 54 of the clipforming assembly to roll against the profile link 66. As a result, whenthe trigger 16 is actuated and moved toward the closed position, theclosure link roller 54 applies a force to the profile link 66. Theresistance of the overload spring 152 will, however, maintain theprofile link 66 in a substantially fixed position unless the forceapplied by the closure link roller 54 increases to a force that isgreater than the resistance, e.g., a threshold force. This can be causedby, for example, a foreign object positioned between the jaws 20 or whenthe jaws 20 are fully closed with the clip and vessel, duct, shunt, etc.therebetween. When the jaws 20 cannot be further closed, the forceapplied to the closure link roller 54 from the closing motion of thetrigger 16 will be transferred to the profile link 66, which will thenpivot and slide within the housing 64, thereby causing the pivot link 70to pivot, which forces the plunger 154 to compress the overload spring152.

As previously noted, the force required to actuate the overloadmechanism can correlate to the force required to close the jaws 20,which increases as the trigger 16 is moved to the closed position. Thiscan be achieved due to the configuration of the profile link 66. Inparticular, when the closure link roller 54 first comes into contactwith the profile link 66 and is thus in a lower position, the profilelink 66 can pivot within the housing 64, as shown in FIG. 23B. As theclosure link roller 54 moves upward along the profile link 66, the forcerequired to overcome the resistance of the overload mechanism increasesbecause the profile link 66 must slide within the housing 64, as shownin FIG. 23C. The force required to pivot the profile link 66 can be lessthan the force required to slide the profile link 66. Accordingly, ifthe jaws 20 are prevented from being closed, e.g., by a foreign object,as the trigger is initially actuated, a minimal force will be requiredto cause the closure link roller 54 to transfer the force to the lowerportion of the profile link 66 causing the profile link 66 to pivot.When the jaws 20 are substantially closed and the trigger 16 is almostfully actuated, a significant amount of force is required to cause theclosure link roller 54 to transfer the force to the upper portion of theprofile link 66 causing the profile link 66 to slide within the housing64 to overcome the resistance of the overload spring 152. While theamount of force required to actuate the overload mechanism can begreater than and can increase relative to the amount of force requiredto close the jaws 20, the force is preferably only slightly greater thanthe force required to close the jaws 20 to prevent deformation or otherdamage to the jaws 20. A person skilled in the art will appreciate thatthe resistance can be adjusted based on the force necessary to close thejaws 20.

The profile link 66, and in particular the distal-facing surface 66 s ofthe profile link 66, can also have a shape that facilitates correlationbetween the force required to actuate the overload mechanism and theforce required to close the jaws 20. For example, where the forcerequired to close the jaws 20 increases at a linear rate, thedistal-facing surface 66 s of the profile link 66 can be planar toprevent the profile link 66 from interfering with movement of theclosure link roller 54 there over, and to allow a linear force to beapplied to the trigger 16 to close the jaws 20. Conversely, where theforce required to close the jaws 20 is non-linear as the trigger 16 ismoved to the closed position, the profile link 66 can have a non-linearshape that corresponds to the non-linear force. Such a configurationwill prevent the forces required to close the cam 42 (FIG. 8) frombecoming too high.

By way of non-limiting example, the force required to close the jaws 20can be non-linear due to the shape of the recess 104 in the cam 42 thatis adapted to push the jaw members 96 a, 96 b toward one another. Asshown in FIG. 8, the recess 104 can have a curved configuration suchthat the force will vary as the cam 42 passes over the jaw members 96 a,96 b. The profile link 66 can therefore having a corresponding curveddistal-facing surface such that the force will also vary as the closurelink roller 54 passes there over. As shown in FIGS. 23A and 23B, theprofile link 66 is curved such that the lower portion of the profilelink 66 is substantially convex and the upper portion of the profilelink 66 is substantially concave. A person skilled in the art willappreciate that the profile link 66 can have a variety of other shapes,and that a variety of other techniques can be used to optimize the forcenecessary to close the jaws 20 and the force necessary to actuate theoverload mechanism.

A person skilled in the art will also appreciate that the overloadmechanism can have a variety of other configurations. By way ofnon-limiting example, FIG. 23D illustrates an overload mechanism that isin the form of a cantilevered beam 170 for receiving a force applied bythe closure link roller 54. The beam 170 can have a substantially curvedmember 172 with a bracket 174 coupled to one end thereof. The curvedmember 172 can have a bending moment that, when loaded with a forcegreater then the bending moment, buckles to assume a low rigiditycondition. The bracket 174 can provide more rigidity to the curvedmember 172 such that the bending moment increases adjacent to thebracket 174. In use, the beam 170 can be loaded within the housing 12 ofthe clip applier 10 such that the closure link roller 54 contacts theconcave surface, and the beam 170 can be positioned at an angle suchthat the closure link roller 54 is farther away from the beam when thetrigger 16 is initially actuated, and the closure link roller 54 becomescloser to the beam as the trigger 16 moves to the closed position. As aresult, the resistance to buckling will increase as the closure linkroller 54 moves thereof and the trigger 16 of the clip applier is movedto the closed position. Although not shown, multiple beams couldoptionally be used in a stacked fashion and the terminal or free end ofthe beam(s) could be contoured to tailor the buckling load at aparticular point along the length of the beam.

In another exemplary embodiment, the surgical clip applier 10 caninclude a clip quantity indicator for indicating the number of clipsremaining in the device 10. While various techniques can be used toindicate the quantity of clips remaining, FIGS. 24A-25 illustrate oneexemplary embodiment of a clip quantity indicator having an indicatorwheel 74 and an indicator actuator 76.

The indicator wheel 74 is shown in detail in FIGS. 24A and 24B, and asshown it has a generally circular or cylindrical shape that defines acentral axis Y about which the wheel 74 is adapted to rotate. The wheel74 includes teeth 142 formed therearound and adapted to be engaged bythe indicator actuator 76, and an indicator member 144. The indicatormember 144 can have a variety of configurations, but in an exemplaryembodiment the indicator member 144 is in the form of a contrastingcolor pad having a color, e.g., orange, red, etc., that differs from theremainder of the indicator wheel 74.

FIG. 25 illustrates the exemplary indicator actuator 76 in more detail.The actuator 76 is adapted to be slidably disposed within the housing 12and to couple to the feed link coupler 50 and move as the feed barcoupler 50 and feed bar 38 are moved. Accordingly, the indicatoractuator 76 can include a protrusion 146, only a portion of which isshown, formed on an inferior surface thereof for extending into therecess 50 f formed between the circular flanges 50 d, 50 e on the feedbar coupler 50. The protrusion 146 allows the indicator actuator 76 tobe engaged by the feed bar coupler 50 and moved therewith. The indicatoractuator 76 can also include an engagement mechanism 148 formed thereonand adapted to engage the teeth 142 formed on the indicator wheel 74. Asshown in FIG. 25, the engagement mechanism 148 on the indicator actuator76 is in the form of an arm having a tab formed on the end thereof forengaging the teeth 142.

In use, the indicator wheel 74 is rotatably disposed within the housing12, as shown in FIGS. 26A-26B, and the indicator actuator 76 is slidablydisposed within the housing 12 such that the engagement mechanism 148 ispositioned adjacent to the indicator wheel 74 and the protrusion 146extends into the feed bar coupler 50. The housing 12 includes a window12 a formed therein for providing visual access to the indicator wheel144. As the trigger 16 is moved to the closed position and the feed barcoupler 50 is moved distally, the indicator actuator 76 will movedistally with the feed bar 38 and feed bar coupler 50. As a result, theengagement mechanism 148 on the indicator actuator 76 will engage theteeth 142 on the indicator wheel 74, thereby causing the wheel 74 torotate as a clip is advanced into the jaws 20. Each time the trigger 16is actuated to advance a clip 20 into the jaws 20, the indicatoractuator 74 rotates the indicator wheel 76. When the clip supply has twoor three clips left, the contrasting color pad 144 on the indicatorwheel 74 will begin to appear in the window 12 a formed in the housing12, thereby indicating to the user that only a few clips remain. Thecontrasting color pad 144 can be adapted to occupy the entire window 12a when the clip supply is depleted.

In another exemplary embodiment, the indicator wheel 74 can include ananti-backup mechanism that is adapted to prevent the indicator wheel 74from rotating in a reverse direction, e.g., a counter-clockwisedirection, after being advanced. While the anti-backup mechanism canhave a variety of configurations, in the embodiment shown in FIG. 24Bthe indicator wheel 74 includes opposed arms 73 a, 73 b that extendsubstantially parallel to the axis Y. Each arm 73 a, 73 b has a pawl 75a, 75 b formed on a distal-most end thereof that is adapted to engagecorresponding teeth formed on the housing 12. While not shown, thecorresponding teeth can be formed within a circular protrusion formed onan inner portion of the housing 12 adjacent to the window 12 a. When theindicator wheel 74 is disposed within the housing 12, the arms 73 a, 73b extend into the circular protrusion formed around the innercircumference thereof. As a clip is applied and the indicator wheel 74is rotated, the arms 73 a, 73 b can deflect over the teeth in thehousing to move to the next position. When the indicator actuator 76slides proximally to return to its initial position, the arms 73 a, 73 bwill engage the teeth in the housing to prevent the indicator wheel 74from rotating in a reverse direction, i.e., returning to the previousposition. A person skilled in the art will appreciate that a variety ofother techniques can be used to prevent backup of the indicator wheel74.

As previously mentioned, the surgical clip applier 10 can be used toapply a partially or fully closed clip to a surgical site, such as avessel, duct, shunt, etc. In laparoscopic and endoscopic surgery, asmall incision is made in the patient's body to provide access to asurgical site. A cannula or access port is typically used to define aworking channel extending from the skin incision to the surgical site.Often during surgical procedures it is necessary to cease blood flowthrough the vessels or other ducts, and some procedures may require theuse of a shunt. A surgical clip can thus be used to crimp the vessel orto secure the shunt to the vessel. Accordingly, a surgical clip applier,such as clip applier 10, can be introduced through the cannula orotherwise introduced into the surgical site to position the jaws 20around the vessel, shunt, or other duct. The tissue stop 46 canfacilitate positioning of the jaws 20 around the target site. Thetrigger 16 can then be actuated to cause a clip to be advanced betweenthe jaws and positioned around the target site, and to cause the jaws 20to close to crimp the clip. Depending on the intended use of the clip,the trigger 16 can be partially actuated, as indicated by the audiblesound of the pawl 60 reaching the tock tooth 112 b, or it can be fullyactuated. The trigger 16 is then released to release the partially orfully closed clip, and the procedure can be repeated if necessary toapply additional clips.

Various surgical clip appliers and methods are also described in U.S.Pat. No. 7,297,149 entitled “Surgical Clip Applier Methods” and filed onApr. 14, 2005; U.S. Pat. No. 7,288,098 entitled “Force LimitingMechanism For Medical Instrument” and filed on Apr. 14, 2005; U.S. Pat.No. 7,261,724 entitled “Surgical Clip Advancement Mechanism” and filedon Apr. 14, 2005; U.S. Publication No. 2006/0235440 entitled “SurgicalClip Applier Ratchet Mechanism” and filed on Apr. 14, 2005; U.S.Publication No. 2006/0235441 entitled “Surgical Clip Advancement andAlignment Mechanism” and filed on Apr. 14, 2005; U.S. Publication No.2006/0235442 entitled “Clip Applier With Migrational ResistanceFeatures” and filed on Sep. 15, 2005; U.S. Publication No. 2006/0235443entitled “Clip Applier Configured to Prevent Clip Fallout” and filed onSep. 15, 2005; U.S. Publication No. 2006/0235444 entitled “Clip AdvancerMechanism With Alignment Features” and filed on Sep. 15, 2005; U.S.Publication No. 2008/0015615 entitled “Surgical Clip AdvancementMechanism” and filed on Jul. 23, 2007; U.S. Publication No. 2008/0004639entitled “Force Limiting Mechanism for Medical Instrument” and filed onSep. 14, 2007; U.S. Publication No. 2008/0027465 entitled “Surgical ClipApplier Methods” and filed on Oct. 9, 2007; U.S. Publication No.2008/0027466 entitled “Surgical Clip Applier Methods” and filed on Oct.9, 2007; and U.S. application Ser. No. 12/576,736 entitled “ImprovedClip Advancer” and filed on Oct. 9, 2009, all of which are incorporatedherein by reference in their entireties.

One skilled in the art will appreciate further features and advantagesof the invention based on the above-described embodiments. Accordingly,the invention is not to be limited by what has been particularly shownand described, except as indicated by the appended claims. Allpublications and references cited herein are expressly incorporatedherein by reference in their entirety.

1. A surgical clip applier, comprising: a housing having a triggermovably coupled thereto and an elongate shaft extending therefrom withopposed jaws formed on a distal end thereof; an advancer assemblydisposed within the elongate shaft and configured to advance one of aplurality of clips disposed within the elongate shaft into the opposedjaws, the advancer assembly being movable between a proximal positionand a distal position; and a feeder shoe disposed within the elongateshaft and configured to engage and prevent the advancer assembly frommoving to the proximal position after the advancer assembly has moved tothe distal position to advanced a proximal-most clip into the opposedjaws.
 2. The surgical clip applier of claim 1, wherein movement of thetrigger from an open position to a closed position is effective to movethe advancer assembly from the proximal position to the distal position.3. The surgical clip applier of claim 1, further comprising a clip trackdisposed within the elongate shaft and having a plurality of clipsseated therein.
 4. The surgical clip applier of claim 3, wherein thefeeder shoe is slidably disposed within the clip track to distallyadvance the plurality of clips through the clip track.
 5. The surgicalclip applier of claim 1, wherein the advancer assembly includes a recessformed therein that is configured to be engaged by a tang on the feedershoe to prevent the advancer assembly from moving to the proximalposition after the advancer assembly has moved a proximal-most clip intothe opposed jaws.
 6. The surgical clip applier of claim 5, wherein thetang on the feeder shoe is configured to move distally with the feedershoe as the feeder shoe advances the plurality of clips through the cliptrack.
 7. The surgical clip applier of claim 5, wherein the advancerassembly comprises a feed bar coupled to an advancer, the advancerhaving a distal end configured to contact and advance one of a pluralityof clips into the opposed jaws.
 8. The surgical clip applier of claim 7,wherein the recess is formed through a distal portion of the feed barand a proximal portion of the advancer.
 9. The surgical clip applier ofclaim 5, wherein a proximal portion of the tang is connected to thefeeder shoe and a distal portion of the tang is disconnected from thefeeder shoe and extends a distance below an inferior surface of thefeeder shoe.
 10. A surgical clip applier, comprising: a handle housinghaving a trigger movably coupled thereto and an elongate shaft extendingdistally therefrom, the elongate shaft having opposed jaws on a distalend thereof; a clip advancing assembly operatively associated with thetrigger and configured to advance one of a plurality of clips disposedwithin the elongate shaft into the opposed jaws; and a lockout mechanismconfigured to lock the clip advancing assembly in place after the clipadvancing assembly has distally advanced a proximal-most clip into theopposed jaws, the clip advancing assembly configured to lock the triggerin an actuated position when the clip advancing assembly is locked inplace by the lockout mechanism.
 11. The surgical clip applier of claim10, further comprising a pawl and ratchet mechanism disposed within thehandle housing and operatively associated with the trigger, the pawl andratchet mechanism having an engaged configuration in which the pawl andratchet mechanism controls movement of the trigger and a disengagedconfiguration in which the trigger is movable independently of the pawland ratchet mechanism.
 12. The surgical clip applier of claim 11,wherein the lockout mechanism is configured to lock the pawl and ratchetmechanism in an engaged configuration after the clip advancing assemblyhas advanced a proximal-most clip into the opposed jaws to thereby lockthe trigger in an actuated position.
 13. The surgical clip applier ofclaim 11, wherein the trigger is movable in a first direction from afully open position to a fully closed position, and a second directionfrom the fully closed position to the fully open position, and whereinthe trigger is limited to movement in only one of the first and seconddirections when the pawl and ratchet mechanism are in the engagedconfiguration, and the trigger is freely movable in both the first andsecond directions when the pawl and ratchet mechanism are in thedisengaged configuration.
 14. The surgical clip applier of claim 11,wherein the ratchet mechanism includes a series of teeth for engagingthe pawl.
 15. The surgical clip applier of claim 10, wherein the clipadvancing assembly comprises a feeder shoe and an advancer assembly. 16.The surgical clip applier of claim 15, wherein the lockout mechanismcomprises a tang formed on the feeder shoe that is configured forlocking engagement with a recess formed in the advancer assembly afterthe advancer assembly advances a proximal-most clip into the opposedjaws.
 17. The surgical clip applier of claim 15, wherein an inferiorsurface of the feeder shoe is in slidable engagement with a superiorsurface of the advancer assembly.
 18. The surgical clip applier of claim10, wherein the opposed jaws are configured to open and release aproximal-most clip before the lockout mechanism locks the clip advancingassembly.
 19. A method for advancing surgical clips, comprising: movinga trigger from an open-most position to a closed-most position tocorrespondingly advance a proximal-most clip of a plurality of clipsinto opposed jaws of a clip applier; and releasing the trigger such thatthe trigger is locked in an actuated position between the open-most andclosed-most positions to prevent the trigger from being moved to theopen-most position.
 20. The method of claim 19, wherein a tang formed ona feeder shoe is engaged by a recess formed in an advancer assembly tolock the trigger.
 21. The method of claim 20, wherein moving the triggerfrom the open-most position to the closed-most position moves theadvancer assembly distally over the feeder shoe to advance theproximal-most clip into the opposed jaws of the clip applier andreleasing the trigger moves the advancer assembly proximally over thefeeder shoe until the recess in the advancer assembly engages the tangon the feeder shoe.
 22. The method of claim 19, further comprisingreleasing the proximal-most clip from the opposed jaws of the clipapplier before the trigger is locked in an actuated position between theopen-most and closed-most positions to prevent the trigger from beingmoved to the open-most position.